fire alarm vs alert

fire alarm and alert both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire alarm	Yes	No	No	No
alert	Yes	Yes	Yes	No

As nouns, alert is a hypernym of fire alarm; that is, alert is a word with a broader meaning than fire alarm:

Other hypernyms of fire alarm include alarm, alarum, warning signal.

fire alarm (noun)	alert (noun)
an alarm that is tripped off by fire or smoke	a warning serves to make you more alert to danger
a shout or bell to warn that fire has broken out	an automatic signal (usually a sound) warning of danger
	condition of heightened watchfulness or preparation for action

fire alarm (adjective)	alert (adjective)
	engaged in or accustomed to close observation
	mentally perceptive and responsive
	quick and energetic

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