boxershorts vs underdrawers

boxershorts and underdrawers both are nouns.

Word	Noun	Adjective	Verb	Adverb
boxershorts	Yes	No	No	No
underdrawers	Yes	No	No	No

As nouns, boxershorts and underdrawers are synonyms defined as:

Other synonyms of boxershorts include boxers, drawers, shorts.

boxershorts (noun)	underdrawers (noun)
underpants worn by men	underpants worn by men