Theory:

In a group of given names or objects, if one particular object or name does not relate to the other items in the group, such an object is called Odd One Out.
Example:
1. Turtles, crocodiles, frogs, dogs - In this list, dogs are the only animals which survive only on land,  whereas other animals survive both on land and in water. Therefore the odd one out is "dogs".
2. Chess, carrom, cricket, ludo - In this list, chess, carrom and ludo are indoor games, whereas cricket is an outdoor game. Therefore "cricket" is the odd one out.
3. Hope, patience, anger, positivity - In this list, the good qualities are hope, patience and positivity, while one bad quality is anger. Therefore, "anger" is the odd one out.
List of sports with the odd one out (for practice):
 
List
Odd one out
Reason
Hide and seek, kabaddi, kho-kho, tennikoit.Hide and seekOthers are formal sports.
Badminton, cycling, squash, tennis.CyclingOthers are similar games.
Snooker, polo, five pins, carrom board.PoloOthers are indoor games.
Cricket, base ball, hockey, basket ball.Basket ballOthers are played with bat/stick and ball.
Weight-lifting, silambam, boxing, fencing.Weight-liftingOthers are types of martial arts(self-defence).
Cricket, football, boxing, hockey. BoxingOthers are played with a team.
Walking, relay, swimming, cycling.WalkingOthers are formal sports.
Cricket, football, swimming, cycling.SwimmingOthers are land sports.
Cycling, swimming, football, running.FootballOthers are played individually.
Cricket, hockey, football, bowling.BowlingOthers are outdoor sports.
Cricket, hockey, badminton, tennis.BadmintonOther sports require a ball.
Chess, carrom, cricket.CricketOther sports require mind skill only.