goof

nouns

a man who is a stupid incompetent fool
bozo, cuckoo, fathead, goof, goofball, goose, jackass, twat, zany
is derived from
goofy
a person who amuses others by ridiculous behavior
buffoon, clown, goof, goofball, merry andrew
is derived from
goofy

verbs

commit a faux pas or a fault or make a serious mistake
"I blundered during the job interview"
blunder, boob, drop the ball, goof, sin