i Register
In some senses, barmy is marked as archaic, figuratively, informal, British. Watch for register when choosing this word.
adj
Containing, covered with, or pertaining to barm (“foam rising upon beer or other malt liquors when fermenting, used as leaven in brewing and making bread”).
[T]each thy Incubus to Poëtize, / And throvve abroad thy ſpurious Snotteries, / Vpon that puft-vp Lumpe of Barmy froth, […]
Their jovial Nights, in frollicks and in play / They paſs, to drive the tedious Hours avvay. / And their cold Stomachs vvith crovvn'd Goblets cheer, / Of vvindy Cider, and of barmy Beer.
Bubbling with activity or excitement; active, excited.
Just now I've taen the fit o' rhyme, / My barmie noddle's working prime, […]
adj
Crazy, mad; also, eccentric, odd, strange.
[T]he exercise yard of the "barmy fellows," as he called the madmen, (meaning, I suppose, that their brains were in an unnatural state of working,) was but a stone's throw from himself and his rational companions, […]
"Bli'me if I know wot yer all talkin' abaht. You're all barmy on the crumpet," said Liza indignantly, and, turning her back on them, made for home.
Very foolish.