Example : Wore a goofy hat.
A silly idea.
Some wacky plan for selling more books.

Synonyms : goofy, silly, whacky, zany

Example : It used to drive my husband balmy.

Synonyms : around the bend, balmy, barmy, bats, batty, bonkers, buggy, cracked, crackers, daft, dotty, fruity, haywire, kookie, kooky, loco, loony, loopy, nuts, nutty, round the bend, whacky