shorts vs short pants

shorts and short pants both are nouns.

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

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

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

Other synonyms of shorts include trunks.

shorts (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
underpants worn by men