"Gwenog told me she often played herself. Went home in disgust."
-- extract from Gertie Keddle's diary (QA3)
Gertie Keddle’s diary records that her friend Gwenog came over for tea and they then went out and watched some wizards and witches knocking around rocks while flying on broomsticks (QA3).
Gwenog is most likely a made-up Welsh name. Gwen is the feminine form of the name/word Gwyn, meaning "white". Og can mean "a harrow (type of plough)". However "og" can also be added to a noun (eg. "niwl" +og = niwlog "foggy") - as gwenu means "to smile", by extension her name could mean "smiley".
Quidditch lists on the Lexicon: Quidditch