Adjective
1. cockamamie
2. cockamamy, goofy, sappy, silly, wacky, whacky, unreasonable, foolish, buffoonish
Noun
1. clownish, clowlike, humorous, humourous, clown
2. buffoon, merry andrew, fathead
2. goof, goofball, bozo, jackass, goose, cuckoo, twat, fool, sap, saphead, muggins, tomfool