imperfective vs durative aspect

imperfective and durative aspect both are nouns.

Word	Noun	Adjective	Verb	Adverb
imperfective	Yes	No	No	No
durative aspect	Yes	No	No	No

As nouns, durative aspect is a hypernym of imperfective; that is, durative aspect is a word with a broader meaning than imperfective:

imperfective: aspect without regard to the beginning or completion of the action of the verb
durative aspect: the aspect of a verb that expresses its duration

Other hypernyms of imperfective include durative.

imperfective (noun)	durative aspect (noun)
aspect without regard to the beginning or completion of the action of the verb	the aspect of a verb that expresses its duration