Wiktionary
brain fart
alt. (context idiomatic slang English) Something ill-considered and said or done impulsively. n. (context idiomatic slang English) Something ill-considered and said or done impulsively.
Usage examples of "brain fart".
Carrying extras in her bra was easier than breaking into her own apartment or hot-wiring her own car every time she had a brain fart and forgot where she had left something.