restless vs restlessness

restless is not a noun while restlessness is a noun.

Word	Noun	Adjective	Verb	Adverb
restless	No	Yes	No	No
restlessness	Yes	No	No	No

restless (noun)	restlessness (noun)
	inability to rest or relax or be still
	the quality of being ceaselessly moving or active
	a feeling of agitation expressed in continual motion
	a lack of patience; irritation with anything that causes delay

restless (adjective)	restlessness (adjective)
lacking or not affording physical or mental rest
worried and uneasy
ceaselessly in motion
nervous and unable to relax