retain vs keep on

retain and keep on both are verbs.

Word	Noun	Adjective	Verb	Adverb
retain	No	No	Yes	No
keep on	No	No	Yes	No

As verbs, retain and keep on are synonyms defined as:

retain and keep on: allow to remain in a place or position or maintain a property or feature

Other synonyms of retain include continue, keep.

retain (verb)	keep on (verb)
keep in one's mind	allow to remain in a place or position or maintain a property or feature
secure and keep for possible future use or application
allow to remain in a place or position or maintain a property or feature
hold back within