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: social gathering 
Words: picnic, french toast, clan, club, bar
Example Output: french toast

Example Input: Category: type of rigidity 
Words: solid, leverage, hard, unbending, firm
Example Output: leverage

Example Input: Category: direction 
Words: down, lower, opposite of up, ground, remorseful
Example Output:
remorseful