donkusai

slow; stupid; dumb

Word type: I-adjectives

Kanji: 鈍臭い

Standard: とろい

Standard kanji: とろい

Example:

どんくさいやちゃなあ。なんでこんな簡単な問題も分かれへんのや。
You're so dumb--how can you not understand a question this easy?