Synonyms of idiot in English:

fool, ass, halfwit, nincompoop, dunce, dolt, ignoramus, cretin, imbecile, dullard, moron, simpleton, clod

dope, ninny, chump, dimwit, nitwit, goon, dumbo, dum-dum, dumb-bell, loon, dork, jackass, bonehead, fathead, numbskull, blockhead, dunderhead, chucklehead, knucklehead, muttonhead, pudding-head, thickhead, wooden-head, airhead, pinhead, lamebrain, pea-brain, birdbrain, zombie, jerk, nerd, dipstick, donkey, noodle

British nit, twit, numpty, clot, plonker, berk, prat, pillock, wally, git, wazzock, divvy, nerk, twerp, twonk, charlie, mug, muppet

Scottish nyaff, balloon, sumph, gowk

Irish gobdaw

North American schmuck, bozo, boob, lamer, turkey, schlepper, chowderhead, dumbhead, dummy, goofball, goof, goofus, galoot, lummox, klutz, putz, schlemiel, sap, gink, cluck, clunk, ding-dong, dingbat, wiener, weeny, dip, simp, spud, coot, palooka, poop, squarehead, yo-yo, dingleberry

US wing nut

NZ Australian drongo, dill, alec, galah, nong, bogan, poon, boofhead

South African mompara

British vulgar slang knobhead

North American vulgar slang asshat

archaic tomfool, noddy, clodpole, loggerhead, spoony, mooncalf