turn back vs return

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

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

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

Other synonyms of turn back include regress, retrovert, revert.

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

turn back: retrace one's course
return: go or come back to place, condition, or activity where one has been before

turn back (noun)	return (noun)
	the act of going back to a prior location
	a coming to or returning home
	getting something back again
	a tennis stroke that sends the ball back to the other player
	(American football) the act of running back the ball after a kickoff or punt or interception or fumble
	a reciprocal group action
	the act of someone appearing again
	the key on electric typewriters or computer keyboards that causes a carriage return and a line feed
	document giving the tax collector information about the taxpayer's tax liability
	a quick reply to a question or remark (especially a witty or critical one)
	happening again (especially at regular intervals)
	the occurrence of a change in direction back in the opposite direction
	the income or profit arising from such transactions as the sale of land or other property

turn back (verb)	return (verb)
go back to a previous state	go back to a previous state
turn inside out or upside down	be restored
hold back, as of a danger or an enemy; check the expansion or influence of	go back to something earlier
retrace one's course	answer back
force to go away; used both with concrete and metaphoric meanings	submit (a report, etc.) to someone in authority
	pass down
	make a return
	give or supply
	go or come back to place, condition, or activity where one has been before
	return to a previous position; in mathematics
	bring back to the point of departure
	pay back
	return in kind
	give back
	be inherited by
	elect again