bow and arrow vs weapon system

bow and arrow and weapon system both are nouns.

Word	Noun	Adjective	Verb	Adverb
bow and arrow	Yes	No	No	No
weapon system	Yes	No	No	No

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

bow and arrow: a weapon consisting of arrows and the bow to shoot them
weapon system: any instrument or instrumentality used in fighting or hunting

Other hypernyms of bow and arrow include arm, weapon.

bow and arrow (noun)	weapon system (noun)
a weapon consisting of arrows and the bow to shoot them	any instrument or instrumentality used in fighting or hunting