keep back vs baffle

keep back is not a noun while baffle is a noun.

Word	Noun	Adjective	Verb	Adverb
keep back	No	No	Yes	No
baffle	Yes	No	Yes	No

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

keep back (noun)	baffle (noun)
	a flat plate that controls or directs the flow of fluid or energy

keep back (verb)	baffle (verb)
prevent the action or expression of	restrain the emission of (sound, fluid, etc.)
hold back; refuse to hand over or share	be a mystery or bewildering to
secure and keep for possible future use or application	hinder or prevent (the efforts, plans, or desires) of