military personnel vs serviceman

military personnel and serviceman both are nouns.

Word	Noun	Adjective	Verb	Adverb
military personnel	Yes	No	No	No
serviceman	Yes	No	No	No

As nouns, military personnel and serviceman are synonyms defined as:

military personnel and serviceman: someone who serves in the armed forces; a member of a military force

Other synonyms of military personnel include man, military man.

military personnel (noun)	serviceman (noun)
soldiers collectively	someone who serves in the armed forces; a member of a military force
someone who serves in the armed forces; a member of a military force