keep on vs prolong

keep on and prolong both are verbs.

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

As verbs, prolong is a hypernym of keep on; that is, prolong is a word with a broader meaning than keep on:

keep on: allow to remain in a place or position or maintain a property or feature
prolong: lengthen or extend in duration or space

Other hypernyms of keep on include keep up, sustain.

keep on (verb)	prolong (verb)
allow to remain in a place or position or maintain a property or feature	lengthen in time; cause to be or last longer
	lengthen or extend in duration or space