sweetener vs sirup

sweetener and sirup both are nouns.

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

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

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

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