A mildly derogatory term for a foolish or slow-witted person; not extremely harsh but clearly insulting.
That guy is a real dimwit.
Don't say such stupid things.
Kansai dialect equivalent of ばか; うすばか is standard Japanese and slightly milder.
Kanji spelling; rarely used in practice.
Mixed kana/katakana spelling sometimes seen in casual writing.
Compound of 薄 (usu, 'thin, weak') and 馬鹿 (baka, 'fool'), literally 'thin fool'. The exact origin is uncertain, but it likely developed as a colloquial insult.