imprint vs act upon

imprint is a noun but act upon is not a noun.

Word	Noun	Adjective	Verb	Adverb
imprint	Yes	No	Yes	No
act upon	No	No	Yes	No

As verbs, act upon is a hypernym of imprint; that is, act upon is a word with a broader meaning than imprint:

Other hypernyms of imprint include influence, work.

imprint (noun)	act upon (noun)
a device produced by pressure on a surface
a distinctive influence
an impression produced by pressure or printing
an identification of a publisher; a publisher's name along with the date and address and edition that is printed at the bottom of the title page
a concavity in a surface produced by pressing

imprint (verb)	act upon (verb)
mark or stamp with or as if with pressure	have and exert influence or effect
establish or impress firmly in the mind