pants suit vs pantsuit

pants suit and pantsuit both are nouns.

Word	Noun	Adjective	Verb	Adverb
pants suit	Yes	No	No	No
pantsuit	Yes	No	No	No

As nouns, pants suit and pantsuit are synonyms defined as:

pants suit and pantsuit: a pair of pants and a matching jacket worn by women

pants suit (noun)	pantsuit (noun)
a pair of pants and a matching jacket worn by women	a pair of pants and a matching jacket worn by women