1.Definition: affected with madness or insanity

Related Adjective(s):brainsick, demented, disturbed, mad, sick, unbalanced, unhinged

2.Definition: bizarre or fantastic

"Had a crazy dream", "Wore a crazy hat"

3.Definition: foolish; totally unsound

"A crazy scheme"

Related Adjective(s):screwball, softheaded

4.Definition: intensely enthusiastic about or preoccupied with

"Crazy about cars and racing"

Related Adjective(s):dotty, gaga, wild

5.Definition: possessed by inordinate excitement

"The crowd went crazy", "Was crazy to try his new bicycle"