imperfective vs imperfective aspect

imperfective and imperfective aspect both are nouns.

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

As nouns, imperfective and imperfective aspect are synonyms defined as:

imperfective and imperfective aspect: aspect without regard to the beginning or completion of the action of the verb

imperfective (noun)	imperfective aspect (noun)
aspect without regard to the beginning or completion of the action of the verb	aspect without regard to the beginning or completion of the action of the verb