open up vs turn

open up is not a noun while turn is a noun.

Word	Noun	Adjective	Verb	Adverb
open up	No	No	Yes	No
turn	Yes	No	Yes	No

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

Other hypernyms of open up include change state.

open up (noun)	turn (noun)
	the act of changing or reversing the direction of the course
	the act of turning away or in the opposite direction
	taking a short walk out and back
	a favor for someone
	(game) the activity of doing something in an agreed succession
	turning or twisting around (in place)
	a short performance that is part of a longer program
	a movement in a new direction
	an unforeseen development
	a circular segment of a curve
	(sports) a division of a game during which one team is on the offensive
	a time period for working (after which you will be relieved by someone else)

open up (verb)	turn (verb)
make available	twist suddenly so as to sprain
become available	change to the contrary
talk freely and without inhibition	go sour or spoil
cause to open or to become open	pass into a condition gradually, take on a specific property or attribute; become
become open	undergo a transformation or a change of position or action
open up an area or prepare a way	change color
start to operate or function or cause to start operating or functioning	become officially one year older
	have recourse to or make an appeal or request for help or information to
	direct at someone
	shape by rotating on a lathe or cutting device or a wheel
	let (something) fall or spill from a container
	alter the functioning or setting of
	cause (an object) to assume a crooked or angular form
	to break and turn over earth especially with a plow
	to change orientation or direction
	cause to move around a center so as to show another side of
	cause to move around or rotate
	pass to the other side of
	move around an axis or a center
	to send or let go
	cause to move along an axis or into a new direction
	channel one's attention, interest, thought, or attention toward or away from something
	get by buying and selling
	accomplish by rotating
	undergo a change or development
	cause to change or turn into something different;assume new characteristics