alert vs fire alarm

alert and fire alarm both are nouns.

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

As nouns, fire alarm is a hyponym of alert; that is, fire alarm is a word with a more specific, narrower meaning than alert:

Other hyponyms of alert include torpedo, air alert, burglar alarm, foghorn, fogsignal, horn, red flag, siren, alarm bell, tocsin.

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

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

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