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: employment activity 
Words: sack, inferno, promote, empower, fire
Example Output: inferno

Example Input: Category: emotional status 
Words: concerned, board, nervous, emotional, fret
Example Output: board

Example Input: Category: type of sandwich 
Words: grilled cheese, french toast, outing, burger, club
Example Output:
outing