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.

Example Input: Category: elements 
Words: ice, air, fire, hire, combustion
Example Output: hire

Example Input: Category: moral characteristic 
Words: mild, equitable, unprejudiced, trustworthy, fair
Example Output: mild

Example Input: Category: military rank 
Words: general, lieutenant, commander, ordinary, captain
Example Output:
ordinary