pullover vs sweatshirt

pullover and sweatshirt both are nouns.

Word	Noun	Adjective	Verb	Adverb
pullover	Yes	No	No	No
sweatshirt	Yes	No	No	No

As nouns, sweatshirt is a hyponym of pullover; that is, sweatshirt is a word with a more specific, narrower meaning than pullover:

pullover: a sweater that is put on by pulling it over the head
sweatshirt: cotton knit pullover with long sleeves worn during athletic activity

pullover (noun)	sweatshirt (noun)
a sweater that is put on by pulling it over the head	cotton knit pullover with long sleeves worn during athletic activity