overdress vs garment

overdress is not a noun while garment is a noun.

Word	Noun	Adjective	Verb	Adverb
overdress	No	No	Yes	No
garment	Yes	No	Yes	No

As verbs, garment is a hypernym of overdress; that is, garment is a word with a broader meaning than overdress:

Other hypernyms of overdress include apparel, clothe, dress, enclothe, fit out, garb, habilitate, raiment, tog.

overdress (noun)	garment (noun)
	an article of clothing

overdress (verb)	garment (verb)
put on special clothes to appear particularly appealing and attractive	provide with clothes or put clothes on
dress too warmly