useful vs utility

useful is not a noun while utility is a noun.

Word	Noun	Adjective	Verb	Adverb
useful	No	Yes	No	No
utility	Yes	Yes	No	No

useful (noun)	utility (noun)
	the service (electric power or water or transportation) provided by a public utility
	a facility composed of one or more pieces of equipment connected to or part of a structure and designed to provide a service such as heat or electricity or water or sewage disposal
	the quality of being of practical use
	(computer science) a program designed for general support of the processes of a computer
	a company that performs a public service; subject to government regulation
	(economics) a measure that is to be maximized in any situation involving choice

useful (adjective)	utility (adjective)
being of use or service	used of beef; usable but inferior
having a useful function	capable of substituting in any of several positions on a team