hold back vs retain

hold back and retain both are verbs.

Word	Noun	Adjective	Verb	Adverb
hold back	No	No	Yes	No
retain	No	No	Yes	No

As verbs, hold back and retain are synonyms defined as:

hold back and retain: secure and keep for possible future use or application

Other synonyms of hold back include hold, keep back.

hold back (verb)	retain (verb)
prevent the action or expression of	keep in one's mind
hold back, as of a danger or an enemy; check the expansion or influence of	secure and keep for possible future use or application
hold back; keep from being perceived by others	allow to remain in a place or position or maintain a property or feature
secure and keep for possible future use or application	hold back within
wait before acting
refrain from doing