digest vs predigest

digest is a noun but predigest is not a noun.

Word	Noun	Adjective	Verb	Adverb
digest	Yes	No	Yes	No
predigest	No	No	Yes	No

As verbs, predigest is a hyponym of digest; that is, predigest is a word with a more specific, narrower meaning than digest:

Other hyponyms of digest include stomach.

digest (noun)	predigest (noun)
something that is compiled (as into a single book or file)
a periodical that summarizes the news

digest (verb)	predigest (verb)
make more concise	digest (food) beforehand
systematize, as by classifying and summarizing
become assimilated into the body
soften or disintegrate by means of chemical action, heat, or moisture
soften or disintegrate, as by undergoing exposure to heat or moisture
arrange and integrate in the mind
put up with something or somebody unpleasant
convert food into absorbable substances