chicken out vs back off

chicken out and back off both are verbs.

Word	Noun	Adjective	Verb	Adverb
chicken out	No	No	Yes	No
back off	No	No	Yes	No

As verbs, chicken out and back off are synonyms defined as:

Other synonyms of chicken out include back down, bow out, pull out.

chicken out (verb)	back off (verb)
remove oneself from an obligation	move backwards from a certain position
	remove oneself from an obligation