polo-neck vs jumper

polo-neck and jumper both are nouns.

Word	Noun	Adjective	Verb	Adverb
polo-neck	Yes	No	No	No
jumper	Yes	No	No	No

As nouns, jumper is a hypernym of polo-neck; that is, jumper is a word with a broader meaning than polo-neck:

Other hypernyms of polo-neck include jersey, T-shirt, tee shirt, sweater.

polo-neck (noun)	jumper (noun)
a sweater or jersey with a high close-fitting collar	(basketball) a player releases the basketball at the high point of a jump
	a sleeveless dress resembling an apron; worn over other clothing
	a loose jacket or blouse worn by workmen
	a small connector used to make temporary electrical connections
	a coverall worn by children
	a crocheted or knitted garment covering the upper part of the body
	an athlete who competes at jumping
	a person who jumps