We call people fools pretty often, so you can use that term. We also say idiot, dummy, moron, dope, and numbskull.
foo
Halfwit
A baniak is a pejorative slang term for a fool.
American Fool was created in 1981.
Galah, mug, yarra, dingbat.
Blockhead, bonehead, twit, nincompoop
The only deffiniton of Gommie I know of is that it's slang for a fool.
Drongo, galah, mug, yarra, drop kick.
The American slang for language is "lingo" or "jargon."
American Slang was created on 2010-03-01.
try urbandictionary.com
Strictly speaking, "pendejo" is a Spanish word meaning "coward". It also turns up in American hobo slang as a word meaning either a fool or a coward.