pull back vs retreat

pull back is not a noun while retreat is a noun.

Word	Noun	Adjective	Verb	Adverb
pull back	No	No	Yes	No
retreat	Yes	No	Yes	No

As verbs, pull back and retreat are synonyms defined as:

pull back and retreat: make a retreat from an earlier commitment or activity

Other synonyms of pull back include back away, back out, crawfish, crawfish out, pull in one's horns, withdraw.

As verbs, pull back and retreat are synonyms defined as:

Other synonyms of pull back include draw back, move back, pull away, recede, retire, withdraw.

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

Other hyponyms of pull back include fall back, retrograde, back down, back off, back up.

pull back (noun)	retreat (noun)
	(military) withdrawal of troops to a more favorable position to escape the enemy's superior forces or after a defeat
	withdrawal for prayer and study and meditation
	the act of withdrawing or going backward (especially to escape something hazardous or unpleasant)
	an area where you can be alone
	(military) a bugle call signaling the lowering of the flag at sunset
	(military) a signal to begin a withdrawal from a dangerous position
	a place of privacy; a place affording peace and quiet

pull back (verb)	retreat (verb)
make a retreat from an earlier commitment or activity	make a retreat from an earlier commitment or activity
move to a rearward position; pull towards the back	pull back or move away or backward
stretch back a bowstring (on an archer's bow)	move back
use a surgical instrument to hold open (the edges of a wound or an organ)	move away, as for privacy
pull back or move away or backward