Crackup and Off-the-wall

Off-the-wall and crackup are semantically related. In some cases you can use "Off-the-wall" instead an adjective "Crackup".

Off-the-wall adjective - Different from the ordinary in a way that causes curiosity or suspicion.

Crackup and off-the-wall are semantically related. Sometimes you can use "Crackup" instead an adjective phrase "Off-the-wall".