incentive vs rational motive

incentive and rational motive both are nouns.

Word	Noun	Adjective	Verb	Adverb
incentive	Yes	No	No	No
rational motive	Yes	No	No	No

As nouns, rational motive is a hypernym of incentive; that is, rational motive is a word with a broader meaning than incentive:

incentive: a positive motivational influence
rational motive: a motive that can be defended by reasoning or logical argument

incentive (noun)	rational motive (noun)
a positive motivational influence	a motive that can be defended by reasoning or logical argument
an additional payment (or other remuneration) to employees as a means of increasing output