polearm vs weapon system

polearm and weapon system both are nouns.

Word	Noun	Adjective	Verb	Adverb
polearm	Yes	No	No	No
weapon system	Yes	No	No	No

As nouns, weapon system is a hypernym of polearm; that is, weapon system is a word with a broader meaning than polearm:

polearm: a close combat weapon in which the main fighting part of the weapon is fitted to the end of a long shaft, typically of wood, thereby extending the user's effective range.
weapon system: any instrument or instrumentality used in fighting or hunting

Other hypernyms of polearm include arm, weapon.

polearm (noun)	weapon system (noun)
a close combat weapon in which the main fighting part of the weapon is fitted to the end of a long shaft, typically of wood, thereby extending the user's effective range.	any instrument or instrumentality used in fighting or hunting