nucleon vs antiproton

nucleon and antiproton both are nouns.

Word	Noun	Adjective	Verb	Adverb
nucleon	Yes	No	No	No
antiproton	Yes	No	No	No

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

nucleon: a constituent (proton or neutron) of an atomic nucleus
antiproton: an unstable negatively charged proton; the antiparticle of a proton

Other hyponyms of nucleon include antineutron, neutron, proton.

nucleon (noun)	antiproton (noun)
a constituent (proton or neutron) of an atomic nucleus	an unstable negatively charged proton; the antiparticle of a proton