the.com/goon

means A thuggish enforcer hired for intimidation or violence rather than brains — muscle for hire, not a thinker.

from Murky, but the likeliest trail runs through 'gooney,' old slang for a fool or simpleton, which by the 1920s American underworld had curdled into 'goon' for a dim hired thug. The word got a pop-culture boost from the Alice the Goon character in the Popeye comics of the early 1930s — a hulking, grunting enforcer — which may have cemented the word's modern 'muscle for hire' sense even if it didn't start it.