rival vs competition

rival and competition both are nouns.

Word	Noun	Adjective	Verb	Adverb
rival	Yes	Yes	Yes	No
competition	Yes	No	No	No

As nouns, rival and competition are synonyms defined as:

Other synonyms of rival include challenger, competitor, contender.

rival (noun)	competition (noun)
the contestant you hope to defeat	the act of competing as for profit or a prize
	an occasion on which a winner is selected from among two or more contestants
	the contestant you hope to defeat
	a business relation in which two parties compete to gain customers

rival (adjective)	competition (adjective)
as a rival in a competition

rival (verb)	competition (verb)
be the rival of, be in competition with
be equal to in quality or ability