backing vs strengthener

backing and strengthener both are nouns.

Word	Noun	Adjective	Verb	Adverb
backing	Yes	No	No	No
strengthener	Yes	No	No	No

As nouns, strengthener is a hypernym of backing; that is, strengthener is a word with a broader meaning than backing:

Other hypernyms of backing include bed, layer, reinforcement.

backing (noun)	strengthener (noun)
the act of providing approval and support	a device designed to provide additional strength
something forming a back that is added for strengthening
financial resources provided to make some project possible