garment vs overdress

garment is a noun but overdress is not a noun.

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

As verbs, overdress is a hyponym of garment; that is, overdress is a word with a more specific, narrower meaning than garment:

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

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