hot pants vs shorts

hot pants and shorts both are nouns.

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

As nouns, shorts is a hypernym of hot pants; that is, shorts is a word with a broader meaning than hot pants:

hot pants: skin-tight very short pants worn by young women as an outer garment
shorts: (used in the plural) trousers that end at or above the knee

Other hypernyms of hot pants include short pants, trunks.

hot pants (noun)	shorts (noun)
skin-tight very short pants worn by young women as an outer garment	(used in the plural) trousers that end at or above the knee
a state of sexual arousal	underpants worn by men