expression, godan verb (-ru)
to have a screw loose; to be mentally troubled
Internet slang derived from メンヘラ (mentally troubled person). Describes someone acting unstable or losing their mental composure, often in a self-deprecating or casual online context.
See also: メンヘラ
最近ストレスでメンがヘラってる。
Lately I've been losing it from stress.
あの人のツイート見てると、ちょっとメンがヘラってる気がする。
Looking at that person's tweets, I feel like they're a bit mentally off.