knee pants vs knickers

knee pants and knickers both are nouns.

Word	Noun	Adjective	Verb	Adverb
knee pants	Yes	No	No	No
knickers	Yes	No	No	No

As nouns, knee pants and knickers are synonyms defined as:

knee pants and knickers: (used in the plural) trousers ending above the knee

Other synonyms of knee pants include breeches, knee breeches, knickerbockers.

knee pants (noun)	knickers (noun)
(used in the plural) trousers ending above the knee	(used in the plural) underpants worn by women
	(used in the plural) trousers ending above the knee