crazy
n.n. very strange, foolish, or unusual. You can also use it to describe someone who is very excited or angry.
n. mentally deranged or extremely foolish; manifesting a lack of reason or restraint. Often used informally to describe intense enthusiasm or excessive activity.
The traffic in the city is absolutely crazy today.
The fans went crazy when the singer finally walked onto the stage and started the show.
While the plan seemed crazy to the conservative board members, the younger investors saw it as a bold and necessary risk for the company's survival.
From craze (“to crush”) + -y, akin to being "crazed up". Compare cracked up (“suffered a mental breakdown; be insane”), crackpot. Compare typologically Russian чо́кнутый (čóknutyj).
Commonly functions as a predicative adjective after 'be' or 'go'; when used to describe people, it is often informal and can be insensitive depending on the context.
He is crazy for the footballHe is crazy about footballWhen expressing a strong liking for a hobby or subject, use the preposition 'about' rather than 'for'.