volition vs mental faculty

volition and mental faculty both are nouns.

Word	Noun	Adjective	Verb	Adverb
volition	Yes	No	No	No
mental faculty	Yes	No	No	No

As nouns, mental faculty is a hypernym of volition; that is, mental faculty is a word with a broader meaning than volition:

volition: the capability of conscious choice and decision and intention
mental faculty: one of the inherent cognitive or perceptual powers of the mind

Other hypernyms of volition include faculty, module.

volition (noun)	mental faculty (noun)
the act of making a choice	one of the inherent cognitive or perceptual powers of the mind
the capability of conscious choice and decision and intention