Ray, I found the following HERE

The original meaning of "goon," however, had nothing to do with unions. "Goon" first appeared around 1921 meaning "a dull or stupid person, an oaf," most likely derived from the English dialect word "gooney," meaning "simpleton." The use of "goon" to mean "a stupid person" got a big boost from the appearance in 1933 of a character named "Alice the Goon" in the popular "Thimble Theater" (a/k/a "Popeye") comic strip.

The use of "goon" to mean "hired thug" probably derived from this "idiot" sense, but another theory (proposed by Hugh Rawson in his excellent book "Wicked Words") traces it to the Hindi word "gunda," meaning "hired tough," apparently often spelled "goondah" in British newspapers of the 1920s.

--Stewie.