trunks vs short pants

trunks and short pants both are nouns.

Word	Noun	Adjective	Verb	Adverb
trunks	Yes	No	No	No
short pants	Yes	No	No	No

As nouns, trunks and short pants are synonyms defined as:

trunks and short pants: (used in the plural) trousers that end at or above the knee

Other synonyms of trunks include shorts.

trunks (noun)	short pants (noun)
(used in the plural) trousers that end at or above the knee	(used in the plural) trousers that end at or above the knee