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: employment activity 
Words: promote, ice, retire, ban, fire

SOLUTION: ice

PROBLEM: Category: mode of transportation 
Words: dive, fly, soar, jog, wave

SOLUTION: dive

PROBLEM: Category: type of rigidity 
Words: corporation, firm, stiff, tough, unbending

SOLUTION:
corporation