kneecap vs kneepan

kneecap and kneepan both are nouns.

Word	Noun	Adjective	Verb	Adverb
kneecap	Yes	No	Yes	No
kneepan	Yes	No	No	No

As nouns, kneecap and kneepan are synonyms defined as:

kneecap and kneepan: a small flat triangular bone in front of the knee that protects the knee joint

Other synonyms of kneecap include patella.

kneecap (noun)	kneepan (noun)
a small flat triangular bone in front of the knee that protects the knee joint	a small flat triangular bone in front of the knee that protects the knee joint

kneecap (verb)	kneepan (verb)
shoot in the kneecap, often done by terrorist groups as a warning