brisk vs alert

brisk is not a noun while alert is a noun.

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

As adjectives, brisk and alert are synonyms defined as:

Other synonyms of brisk include lively, merry, rattling, snappy, spanking, zippy.

brisk (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

brisk (adjective)	alert (adjective)
very active	engaged in or accustomed to close observation
quick and energetic	mentally perceptive and responsive
imparting vitality and energy	quick and energetic

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