A mildly derogatory term for a foolish, slow-witted, or lazy person. Often used in casual, colloquial speech. The prefix うすら- adds a nuance of 'somewhat' or 'a bit', softening the insult compared to 馬鹿 alone.
That guy is a dimwit, so it's no use saying anything to him.
Don't say such stupid things.
Kanji spelling using 薄ら and 馬鹿; rarely used and may appear in older or stylized writing.
Mixed kanji-kana spelling; uncommon but occasionally seen.
Mixed kanji-katakana spelling; very rare and stylistically marked.
Derived from the prefix うすら (meaning 'slight' or 'somewhat') attached to 馬鹿 (fool). The exact historical origin of うすら is uncertain, but it is related to 薄い (thin, weak).