unalert vs alert

unalert is not a noun while alert is a noun.

Word	Noun	Adjective	Verb	Adverb
unalert	No	Yes	No	No
alert	Yes	Yes	Yes	No

unalert (noun)	alert (noun)
	a warning serves to make you more alert to danger
	an automatic signal (usually a sound) warning of danger
	condition of heightened watchfulness or preparation for action

unalert (adjective)	alert (adjective)
not alert to what is potentially dangerous	engaged in or accustomed to close observation
	mentally perceptive and responsive
	quick and energetic

unalert (verb)	alert (verb)
	warn or arouse to a sense of danger or call to a state of preparedness