gunner vs serviceman

gunner and serviceman both are nouns.

Word	Noun	Adjective	Verb	Adverb
gunner	Yes	No	No	No
serviceman	Yes	No	No	No

As nouns, serviceman is a hypernym of gunner; that is, serviceman is a word with a broader meaning than gunner:

gunner: a serviceman in the artillery
serviceman: someone who serves in the armed forces; a member of a military force

Other hypernyms of gunner include man, military man, military personnel.

gunner (noun)	serviceman (noun)
a serviceman in the artillery	someone who serves in the armed forces; a member of a military force