compress vs tamp down

compress is a noun but tamp down is not a noun.

Word	Noun	Adjective	Verb	Adverb
compress	Yes	No	Yes	No
tamp down	No	No	Yes	No

As verbs, tamp down is a hyponym of compress; that is, tamp down is a word with a more specific, narrower meaning than compress:

Other hyponyms of compress include pack, tamp.

compress (noun)	tamp down (noun)
a cloth pad or dressing (with or without medication) applied firmly to some part of the body (to relieve discomfort or reduce fever)

compress (verb)	tamp down (verb)
squeeze or press together	press down tightly
make more compact by or as if by pressing