flexible joint vs hinge

flexible joint and hinge both are nouns.

Word	Noun	Adjective	Verb	Adverb
flexible joint	Yes	No	No	No
hinge	Yes	No	Yes	No

As nouns, flexible joint and hinge are synonyms defined as:

flexible joint and hinge: a joint that holds two parts together so that one can swing relative to the other

flexible joint (noun)	hinge (noun)
a joint that holds two parts together so that one can swing relative to the other	a joint that holds two parts together so that one can swing relative to the other
	a circumstance upon which subsequent events depend

flexible joint (verb)	hinge (verb)
	attach with a hinge