TASK DEFINITION: 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.
PROBLEM: Category: type of rigidity 
Words: inflexible, tough, taut, firm, leverage

SOLUTION: leverage

PROBLEM: Category: personal characteristic 
Words: freezing, calm, positive, cool, popular

SOLUTION: freezing

PROBLEM: Category: temperature 
Words: refreshing, tropical, cool, warm, level

SOLUTION:
level