1) Antagonism 2) Army versus Navy 3) Art game 4) Competition 5) Competitiveness 6) Contention 7) Group action 8) Linux game 9) Opposition 10) Siblings may engage in it 11) Struggle 12) Windows game 1) Competition 2) Envy 3) Trouble 
[economics] In economics, rivalry is a characteristic of a good. A good can be placed along a continuum ranging from rivalrous (rival) to non-rival. The same characteristic is sometimes referred to as subtractable or non-subtractable. A rival (subtractable) good is a good whose consumption by one consumer prevents simultaneous consumption b...
• (n.) The act of rivaling, or the state of being a rival; a competition.
[Noun] Trying to equal or beat another.
Competition between two or more individuals for the same object or goal. ... Origin: L. Rivalis, competitor, rival ... (05 Mar 2000) ... 
(ri´vәl-re) a state of competition or antagonism. sibling rivalry competition between siblings for the love, affection, and attention of one or both parents or for other recognition or gain.
Ri'val·ry noun ; plural Rivalries The act of rivaling, or the state of being a rival; a competition. 'Keen contention and eager rivalries .' Jeffrey. Syn. -- Emulation; competition. See Emulation . 
Type: Term Pronunciation: rī′văl-rē Definitions: 1. Competition between two or more individuals or entities for the same object or goal.