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: chocolate food 
Words: cake, fudge, rich, invent, cream
Example Output: invent

Example Input: Category: emotional status 
Words: left, emotional state, sad, emotional upsets, down
Example Output: left

Example Input: Category: chocolate food 
Words: chocolate, cookies, loosen, fudge, brownie
Example Output:
loosen