sweetener vs syrup

sweetener and syrup both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweetener	Yes	No	No	No
syrup	Yes	No	No	No

As nouns, syrup is a hyponym of sweetener; that is, syrup is a word with a more specific, narrower meaning than sweetener:

Other hyponyms of sweetener include aspartame, honey, saccharin, refined sugar, sugar, sirup, cyclamate.

sweetener (noun)	syrup (noun)
anything that serves as an enticement	a thick sweet sticky liquid
something added to foods to make them taste sweeter