turn back vs reverse

turn back is not a noun while reverse is a noun.

Word	Noun	Adjective	Verb	Adverb
turn back	No	No	Yes	No
reverse	Yes	Yes	Yes	No

As verbs, reverse is a hypernym of turn back; that is, reverse is a word with a broader meaning than turn back:

Other hypernyms of turn back include change by reversal, turn.

As verbs, turn back and reverse are synonyms defined as:

Other synonyms of turn back include invert.

turn back (noun)	reverse (noun)
	(American football) a running play in which a back running in one direction hands the ball to a back running in the opposite direction
	turning in the opposite direction
	the gears by which the motion of a machine can be reversed
	the side of a coin or medal that does not bear the principal design
	an unfortunate happening that hinders or impedes; something that is thwarting or frustrating
	a relation of direct opposition

turn back (adjective)	reverse (adjective)
	of the transmission gear causing backward movement in a motor vehicle
	directed or moving toward the rear
	reversed (turned backward) in order or nature or effect

turn back (verb)	reverse (verb)
go back to a previous state	change to the contrary
turn inside out or upside down	turn inside out or upside down
hold back, as of a danger or an enemy; check the expansion or influence of	reverse the position, order, relation, or condition of
retrace one's course	rule against
force to go away; used both with concrete and metaphoric meanings	cancel officially