Merriam-Webster's Collegiate® Dictionary, 11th Edition
RIVAL
I. noun see: run
Date: 1577
1. one of two or more striving to reach or obtain something that only one can possess, one striving for competitive advantage, companion , associate , one that equals another in desired qualities ; peer ,
II. adjective
Date: 1590
having the same pretensions or claims ; competing,
III. verb (rivaled or rivalled; rivaling or rivalling)
Date: 1605
intransitive verb to act as a rival ; compete , transitive verb to be in competition with, to strive to equal or excel ; emulate , to possess qualities or aptitudes that approach or equal (those of another)