Containing yeast (barm); frothy or foamy; silly or crazy (British slang variant of barmy).
From 'barm' (yeast, from Old English beorma) plus '-ie' diminutive/adjectival suffix. The 'crazy' meaning likely derives from the frothy, bubbling nature of fermentation.
In British slang, 'barmie' means slightly unhinged—the connection to yeast's chaotic bubbling perfectly captures the metaphor of a disordered mind.
Complete word intelligence in one call. Free tier — 50 lookups/day.