From Longman Dictionary of Contemporary Englishbarmybarm‧y /ˈbɑːmi $ ˈbɑːrmi/ adjective British English informal CRAZYslightly crazy That’s a barmy idea.
Examples from the Corpus
barmy• However, his appearance in the witness box in support of Gary Blissett in the John Uzzell case was plain barmy.• She obviously thought he was barmy.• I was fourteen then, I'd seen her in National Velvet, and had been barmy about her ever since.• She's barmy as a bedbug.• A small pastry hat manifested itself low on my brow, giving the missing barmy look to my regalia.Origin barmy (1400-1500) barm “froth that forms on beer when it is being made” 