amnestic aphasia vs aphasia

amnestic aphasia and aphasia both are nouns.

Word	Noun	Adjective	Verb	Adverb
amnestic aphasia	Yes	No	No	No
aphasia	Yes	No	No	No

As nouns, aphasia is a hypernym of amnestic aphasia; that is, aphasia is a word with a broader meaning than amnestic aphasia:

amnestic aphasia: inability to name objects or to recognize written or spoken names of objects
aphasia: inability to use or understand language (spoken or written) because of a brain lesion

amnestic aphasia (noun)	aphasia (noun)
inability to name objects or to recognize written or spoken names of objects	inability to use or understand language (spoken or written) because of a brain lesion