bad job
waste of time, futile task

• He turned over the second page of the memo, saw how much longer it went on, and gave it up as a bad job (HBP1).

balaclava
A woolly covering for the head and neck. The name comes from the site of a battle in the Crimean War; soldiers wore this kind of gear (NSOED).

• Hagrid's face was entirely hidden by a woolly, snow-covered balaclava, but it couldn't possibly be anyone else... (CS11)

• ...Hagrid burst in, a wild look in his eyes, his balaclava perched on top of his shaggy black head... (CS12)

• Charlie was darning a fireproof balaclava (GF10).

• Cho was passing, accompanied by Marietta Edgecombe, who was wearing a balaclava.
  - friends don't let friends mess with Hermione Granger (OP38)

bandy-legged
U.S.: bow-legged.

• Hermione's bandy-legged ginger cat, Crookshanks (GF5)

barking, barking mad
wacky, nuts, insane

• "Barking," said Uncle Vernon, "howling mad, the lot of them. You'll see. You just wait." (PS6)

• "Barking mad"
  - Ron on Hermione (GF20)

• "It's not my fault she's barking mad"
  - Harry referring to Madam Pince (HBP15)

barmy
Crazy, but suggests a silly rather than a dangerous kind of craziness. The word's older sense is "frothy"; "barm" is actually the froth on top of fermenting malt liquor.

• "He said we is free to call him a - a barmy old codger if we likes, sir!"
  - Dobby on Dumbledore (GF21)

• See BARNABAS THE BARMY.

Bath buns
sweet bread rolls with crunchy sugar on top

• Hagrid poured them tea and offered them a plate of Bath buns, but they knew better than to accept, having had too much experience of Hagrid's cooking (PA14)

bathing-costume
U.S.: swimsuit; bathing suit.

• ...he was also wearing the strange assortment of clothes so often chosen by inexperienced wizards trying to look like Muggles: in this case, a frock-coat and spats over a striped one-piece bathing costume (HBP10)

battlements
the 'teeth' shaped parts on top of a castle

• over the battlements and out of sight (HBP27)

bauble
A Christmas tree ornament shaped like a ball and made of coloured glass or similar material.

• "Baubles," said Harry to the Fat Lady, this being the new, festive password. (HBP15)

bedside cabinet
a little chest of drawers for next to the bed
U.S.: nightstand

• "This isn't how we imagined handing over our present," said George grimly, putting down a large wrapped gift on Ron's bedside cabinet and sitting beside Ginny (HBP19).

bell-pull
A cord inside a house which, when pulled, causes a bell to ring in another part of the house to get someone else's attention.

• Most [of the tents] looked almost ordinary; their owners had clearly tried to make them as Muggle-like as possible, but had slipped up by adding chimneys, or bell-pulls, or weather-vanes (GF7)

berk
Idiot, objectionable person. The word is actually derived from a very crude and offensive bit of rhyming slang, but in this form is considered to be inoffensive.

• "If we were sometimes arrogant little berks, you mean," said Sirius. (OP29)

• "That old berk...[t]hought the sun shone out of my brother's every orifice, he did"
  - Aberforth (DH28)

besom
A woman or girl, but this term is derogatory (though it can be used in a joking way). When used like this, it often appears in a phrase such as "old besom" (for an older woman) or "little besom" (for a young woman or girl). The word is also an old word for broom.

• "She ain't answering, you old besom!"
  - Amycus Carrow, most unwisely, to Professor McGonagall (DH30)

bin (binned, bin bag)
A bin is a trashcan, so if something is "binned" it is thrown away in the trash. A "bin bag" is a trash bag.

• ...he had spent most of the holidays wandering the streets, scavenging newspapers from bins along the way (OP1)

• "Fred and George had to hide them all to stop Mum binning them." (OP4)

biscuit
A cookie.

• "Is it true that you shouted at Professor Umbridge?"
  "Yes," said Harry.
  "You called her a liar?"
  "Yes."
  "You told her He-Who-Must-Not-Be-Named is back?"
  "Yes."
  Professor McGonagall sat down behind her desk, watching Harry closely. Then she said, "Have a biscuit, Potter." (OP12)

bit keen, bit rich
See keen, rich.

black beetle
Cockroach.

• ...Harry himself examined silver unicorn horns at twenty-one Galleons each and miniscule, glittery black beetle eyes (five Knuts a scoop).
  - one reason why people should think twice about drinking potions (PS5)

black pudding
A sausage-shaped dish made with blood and suet (animal fat) enclosed in a wrapper made from floury batter (NSOED).

• "Bouillabaise," said Hermione.
  "Bless you," said Ron.
  "It's French," said Hermione, "I had it on holiday summer before last. It's very nice."
  "I'll take your word for it," said Ron, helping himself to black pudding.
  (GF16)

bleeder
A stupid, unpleasant, or contemptible person or thing (NSOED).

• "That treacherous old bleeder!" (DH22)

blighter
an annoying thing or person

• "Devilish tricky little blighters they can be!"
  - Gilderoy Lockhart, just prior to releasing a cage full of pixies (CS6)

blimey
A term of exclamation, a bit like "wow". It's actually a contraction of "God blind me!" (hence variations: "Cor Blimey!" or "Gawd Blimey!")

It's very much a slang term; someone trying to sound sophisticated/well-educated wouldn't use it (at least, if they knew what they were doing). It would sound very unusual for Percy, Hermione, or McGonagall to use it, and it's difficult to imagine Snape ever saying it.

• "Blimey," said the other twin. "Are you ---?" (PS6)

• "Blimey, I'm tired," yawned Fred, setting down his knife and fork at last. (CS3)

• "Blimey," said Mundungus weakly, looking from Mrs. Figg to Harry, and back again. "Blimey, I -" (OP2)

• "Blimey...you reckon it was this sign again?" (DH22)

• "I can't - blimey!" (DH23)

• "Blimey, a baby!" (DH25)

• "Blimey, Neville," said Ron, "there's a time and a place for getting a smart mouth (DH29)."

bloke
U.S.: guy, man. In the U.K., one sense of "guy" is that of a scarecrow-like effigy burnt on Bonfire Night, so saying that someone "looks [like] a guy" carries a different meaning than in the U.S.

• "How can I have hung around you for five years and not think girls are clever?" said Harry, stung by this. "It's the way he writes. I just know the Prince was a bloke, I can tell."
  (HBP25)

• a bit of a slap in the face for everyone who thought he was such a good bloke (DH20)

• the bloke from the Ministry (DH22)

• Amycus, the bloke
  -as opposed to his sister, Alecto (DH29)

boater
A flat-topped, hardened straw hat, with a brim. Often worn as part of the uniform of public schools. The name derives from the fact that the hats were worn by some University scholars, who would go boating on the river, but they became more widely popular as adult headgear in Edwardian times.

• "flat straw hats called boaters" (PS3)

bogey, bogies
boogers, snot

• "If either of you get us caught, I'll never rest until I've learned that Curse of the Bogies Quirrell told us about, and used it on you."
  - Ron (PS9)

• "I saw this young lady perform the most marvelous Bat-Bogey Hex as I was passing her carriage!"
  - Slughorn referring to Ginny Weasley (HBP7)

• Hagrid gave another great snort. Harry rather thought some bogeys landed on the potatoes, and was inwardly thankful that they were not staying for dinner (HBP11).

bog-standard
Common, ordinary, with no frills.

• "We thought it was a bog-standard chicken until it started breathing fire." (OP7)

Bonfire Night
a.k.a. Guy Fawkes Night.
On 5^th November every year, Britain commemorates the Gunpowder Plot, in which Guy (Guido) Fawkes and other extremist Catholics plotted (but failed) to blow up James I and his Parliament. People have firework parties or attend organized displays, and effigies of Guy Fawkes (known as "the guy") are burned on bonfires. The term bonfire is derived from 'bone fire' because, originally, bones were the primary material burnt.

• "Viewers as far apart as Kent, Yorkshire and Dundee have been phoning in to tell me that instead of the rain I promised yesterday, they've had a downpour of shooting stars! Perhaps people have been celebrating Bonfire Night early..." (PS1)

bonnet
(referring to part of an automobile) hood (U.S.); can also mean a hat

• Narrow jets of steam were issuing from under the bonnet (CS5)

boot (British edition only)
(referring to part of an automobile) trunk (U.S.)

• "Not a word to Molly," he whispered to Harry as he opened the boot and showed him how it had been magically expanded so that the luggage fitted easily.
  - Arthur Weasley to Harry (CS5)

bored of
U.S.: bored with

• (DH21)

bottom-of-the-table
Coming in last place in a competition (i.e., last in a tabular listing of the entries).

• If they won by less than three hundred points, they would come second to Ravenclaw; if they lost by a hundred points they would be third behind Hufflepuff and if they lost by more than a hundred, they would be in fourth place and nobody, Harry thought, would ever, ever let him forget that it had been he who had captained Gryffindor to their first bottom-of-the-table defeat in two centuries. (HBP24)

bowler, bowler hat
a small hat with a round top, used to be popular business wear in London (accompanied by umbrella)

Note that this is not strictly British usage.

• [Cornelius Fudge] twirling his green bowler hat as usual (HBP30)

Boxing Day
The first weekday after Christmas day, so called because it used to be traditional to give Christmas-boxes (small presents or tips) on that day to people such as employees of firms providing regular services. (In modern usage the first day rather than the first weekday after Christmas Day is often referred to as Boxing Day instead.)

• Everybody got up late on Boxing Day (GF24)

brew ("do me a brew")
Tea; make and serve a cup of tea.

• "Couldn't do me a brew, I suppose?"
  - Ludo Bagman (GF7)

budge up
Move up, move over.

• "Budge up yeh great lump," said the stranger.
  - Hagrid to Dudley (PS4)

• "Budge up there, move along."
  "Hagrid!"
  Ron and Hermione squeezed together to give Hagrid enough space to join them.
  - (PS11)

budgie, budgerigar
A small parrot-like bird kept as a pet, which in the U.S. is called a parakeet. See also Budgerigar Society.

• The pixies were electric blue and about eight inches high, with pointed faces and voices so shrill it was like listening to a lot of budgies arguing (CS6)

• If [the newsreaders] had reached water-skiing budgerigars, there was nothing else worth hearing (OP1).

bung
Throw or give.

• "Bung him some owl treats"
  - Ron to Harry, speaking of Pig (GF10)

bunk, do a
To run away, flee.

• "He has, to use the common phrase, done a bunk"
  - McGonagall answering the Slytherins' question about Snape (DH31)