retrograde vs retreat

retrograde is not a noun while retreat is a noun.

Word	Noun	Adjective	Verb	Adverb
retrograde	No	Yes	Yes	No
retreat	Yes	No	Yes	No

As verbs, retrograde and retreat are synonyms defined as:

As verbs, retreat is a hypernym of retrograde; that is, retreat is a word with a broader meaning than retrograde:

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

retrograde (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

retrograde (adjective)	retreat (adjective)
of amnesia; affecting time immediately preceding trauma
moving from east to west on the celestial sphere; or--for planets--around the sun in a direction opposite to that of the Earth
going from better to worse
moving or directed or tending in a backward direction or contrary to a previous direction

retrograde (verb)	retreat (verb)
get worse or fall back to a previous condition	make a retreat from an earlier commitment or activity
go back over	pull back or move away or backward
move back	move back
move in a direction contrary to the usual one	move away, as for privacy
move backward in an orbit, of celestial bodies