"To rabbit" means to talk incessantly or gossip idly. It's commonly used among Cockney folk, and is an example of rhyming slang where the actual rhyming word is being omitted; the full phrase is "rabbit and pork".
"I'm not promising I'll tell yeh anythin', mind, but don't go rabbitin' about it here, students aren't s'pposed ter know." (PS14)
Reviewing work already learned or done, especially to prepare for an examination (NSOED).
while teachers were firing revision questions at the class (OP28
A kind of fruitcake. It's supposed to look something like a rock, and even to have a hard surface, but not to resemble a rock quite as closely as Hagrid's version seems to.
The rock cakes almost broke their teeth (PS8)
row (noun or verb)
As a noun, can refer to any loud noise or commotion, but when referring to something people do means a very heated quarrel; the verb sense means "quarrel, argue". (NSOED). It's worth mentioning that "row" used in these senses rhymes with "cow", not with "low".
Mrs. Weasley was still glowering as she kissed Mr. Weasley on the cheek, though not nearly as much as the twins, who had each hoisted their rucksacks onto their backs and walked out without a word to her (GF6)
A milder, dialectal variation on the swear word, "bloody," ruddy referring to something being red-coloured (like blood). Similar and slightly more polite version of "bloody" or "damned," (from blood, Old English = rudig).
"Ruddy stargazers. Not interested in anythin' closer'n the moon." (PS15)
Mrs. Next-Door's runner beans (PA2)