1.
fool, idiot; stupid, silly
A colloquial term for a foolish or stupid person. Strongly associated with the Kansai region, where it is used casually among friends with less bite than バカ. However, in the Kanto region, アホ can sound harsher than バカ.
Regional variation
アホ is the standard insult in the Kansai dialect and is often used playfully between friends. In Kanto, バカ fills the same role and sounds softer, while アホ can come across as stronger. The reverse is true in Kansai — バカ sounds harsher there.
Usage
Often written in katakana (アホ), but hiragana (あほ) is also used. Can function as a na-adjective (アホな) or a noun (アホ). The expression アホみたい means "like an idiot" or "ridiculously."