fail-safe vs safe

fail-safe and safe both are nouns.

Word	Noun	Adjective	Verb	Adverb
fail-safe	Yes	Yes	No	No
safe	Yes	Yes	No	No

fail-safe (noun)	safe (noun)
a mechanism capable of returning to a safe state in case there is a failure or malfunction	strongbox where valuables can be safely kept
	contraceptive device consisting of a sheath of thin rubber or latex that is worn over the penis during intercourse
	a ventilated or refrigerated cupboard for securing provisions from pests

fail-safe (adjective)	safe (adjective)
eliminating danger by compensating automatically for a failure or malfunction	free from danger or the risk of harm
guaranteed not to fail	having reached a base without being put out
	financially safe
	(of an undertaking) secure from risk