romper suit vs garment

romper suit and garment both are nouns.

Word	Noun	Adjective	Verb	Adverb
romper suit	Yes	No	No	No
garment	Yes	No	Yes	No

As nouns, garment is a hypernym of romper suit; that is, garment is a word with a broader meaning than romper suit:

romper suit: a one-piece garment for children to wear at play; the lower part is shaped like bloomers
garment: an article of clothing

romper suit (noun)	garment (noun)
a one-piece garment for children to wear at play; the lower part is shaped like bloomers	an article of clothing

romper suit (verb)	garment (verb)
	provide with clothes or put clothes on