Given a category and a set of five words, find the word from the set that does not belong (i.e. is the least relevant) with the other words in the category. Words are separated by commas.

Category: type of rigidity 
Words: inflexible, tough, taut, firm, leverage
leverage

Category: poker 
Words: level, blind, pack, draw, deck
level

Category: outdoor sport activity 
Words: trap, fish, hiking, wrestle, hamster

hamster