back up vs draw back

back up and draw back both are verbs.

Word	Noun	Adjective	Verb	Adverb
back up	No	No	Yes	No
draw back	No	No	Yes	No

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

Other hypernyms of back up include move back, pull away, pull back, recede, retire, retreat, withdraw.

back up (verb)	draw back (verb)
establish as valid or genuine	use a surgical instrument to hold open (the edges of a wound or an organ)
become or cause to become obstructed	pull back or move away or backward
make a copy of (a computer file) especially for storage in another place as a security copy
move backwards from a certain position
give moral or psychological support, aid, or courage to