ingestion vs sucking

ingestion and sucking both are nouns.

Word	Noun	Adjective	Verb	Adverb
ingestion	Yes	No	No	No
sucking	Yes	No	No	No

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

ingestion: the process of taking food into the body through the mouth (as by eating)
sucking: the act of sucking

Other hyponyms of ingestion include eating, feeding, deglutition, drink, swallow, suck, suction, drinking, imbibing, imbibition.

ingestion (noun)	sucking (noun)
the process of taking food into the body through the mouth (as by eating)	the act of sucking