sergeant vs noncom

sergeant and noncom both are nouns.

Word	Noun	Adjective	Verb	Adverb
sergeant	Yes	No	No	No
noncom	Yes	No	No	No

As nouns, noncom is a hypernym of sergeant; that is, noncom is a word with a broader meaning than sergeant:

sergeant: any of several noncommissioned officer ranks in the Army or Air Force or Marines ranking above a corporal
noncom: a military officer appointed from enlisted personnel

Other hypernyms of sergeant include enlisted officer, noncommissioned officer.

sergeant (noun)	noncom (noun)
a lawman with the rank of sergeant	a military officer appointed from enlisted personnel
any of several noncommissioned officer ranks in the Army or Air Force or Marines ranking above a corporal
an English barrister of the highest rank