romper suit vs romper

romper suit and romper both are nouns.

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

As nouns, romper suit and romper are synonyms defined as:

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

romper suit (noun)	romper (noun)
a one-piece garment for children to wear at play; the lower part is shaped like bloomers	a one-piece garment for children to wear at play; the lower part is shaped like bloomers
	a person who romps or frolics