expression, suru verb (irregular)
do a stupid thing; do something foolish
A common phrase for acting foolishly or making a silly mistake. Often used in self-reproach or to criticize someone's action.
また馬鹿なことをしてしまった。
I did something stupid again.
彼はよく馬鹿なことをする。
He often does foolish things.
Standard kanji spelling for this phrase.
Katakana spelling; used for emphasis or in informal contexts.
The phrase combines 馬鹿 (foolish, stupid) with なこと (thing) and する (to do). The origin of 馬鹿 itself is uncertain, with theories ranging from a Sanskrit loanword to a Japanese compound.