well-off vs rich

well-off is not a noun while rich is a noun.

Word	Noun	Adjective	Verb	Adverb
well-off	No	Yes	No	No
rich	Yes	Yes	No	No

well-off (noun)	rich (noun)
	people who have possessions and wealth (considered as a group)

well-off (adjective)	rich (adjective)
fortunately situated	possessing material wealth
in fortunate circumstances financially; moderately rich	having an abundant supply of desirable qualities or substances (especially natural resources)
	suggestive of or characterized by great expense
	high in mineral content; having a high proportion of fuel to air
	causing indignation due to hypocrisy
	affording an abundant supply
	strong; intense
	marked by great fruitfulness
	pleasantly full and mellow
	marked by richness and fullness of flavor
	containing plenty of fat, or eggs, or sugar
	of great worth or quality
	very productive