directional vs directionality

directional is not a noun while directionality is a noun.

Word	Noun	Adjective	Verb	Adverb
directional	No	Yes	No	No
directionality	Yes	No	No	No

directional (noun)	directionality (noun)
	the property of a microphone or antenna of being more sensitive in one direction than in another
	the property of being directional or maintaining a direction

directional (adjective)	directionality (adjective)
relating to or indicating directions in space
relating to direction toward a (nonspatial) goal
showing the way by conducting or leading; imposing direction on