oppress vs keep down

oppress and keep down both are verbs.

Word	Noun	Adjective	Verb	Adverb
oppress	No	No	Yes	No
keep down	No	No	Yes	No

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

Other hyponyms of oppress include quash, reduce, repress, subdue, subjugate.

oppress (verb)	keep down (verb)
come down on or keep down by unjust use of one's authority	manage not to throw up
cause to suffer	place a limit on the number of
	put down by force or intimidation