Synonyms for Goon:

n.

maniac, attack, Crimes, gorilla, dumb blond, fool, joker, numpty, clown. bruiser, gamekeeper, concierge, caretaker, attack dog, gatekeeper, bodyguard, custodian, beefeater, doorkeeper. boor (noun)
lout, oaf.
dolt (noun)
fool.
gangster (noun)
hoodlum, bruiser, tough.
goon (noun)
hoodlum, bruiser, gorilla, clod, lout, klutz, tough, lump, lubber, thug, gawk, punk, hood, toughie, stumblebum, oaf, strong-armer, lummox.
hood/hoodlum (noun)
punk.
lout (noun)
clod, lout.
lummox (noun)
klutz.

Other synonyms:

gorilla. Other relevant words:
bruiser, fool, gorilla, bodyguard.