hold down vs keep back

hold down and keep back both are verbs.

Word	Noun	Adjective	Verb	Adverb
hold down	No	No	Yes	No
keep back	No	No	Yes	No

As verbs, keep back is a hypernym of hold down; that is, keep back is a word with a broader meaning than hold down:

Other hypernyms of hold down include hold, hold back, retain.

hold down (verb)	keep back (verb)
restrain	prevent the action or expression of
keep	hold back; refuse to hand over or share
	secure and keep for possible future use or application