sweetening vs saccharin

sweetening and saccharin both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweetening	Yes	No	No	No
saccharin	Yes	No	No	No

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

sweetening: something added to foods to make them taste sweeter
saccharin: a crystalline substance 500 times sweeter than sugar; used as a calorie-free sweetener

Other hyponyms of sweetening include aspartame, honey, refined sugar, sugar, sirup, syrup, cyclamate.

sweetening (noun)	saccharin (noun)
the act of adding a sweetener to food	a crystalline substance 500 times sweeter than sugar; used as a calorie-free sweetener
an improvement that makes something more agreeable
something added to foods to make them taste sweeter