competition has 7 distinct synonyms spread across 3 of its 4 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is cooperation.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a business relation in which two parties compete to gain customers
“business competition can be fiendish at times”
an occasion on which a winner is selected from among two or more contestants
the act of competing as for profit or a prize
“the teams were in fierce contention for first place”
the contestant you hope to defeat
“he had respect for his rivals”
Synonyms, antonyms and the broader and narrower relations for competition come from Princeton University’s WordNet. Full sources and licences.