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: physical property 
Words: sugars, obese, big boned, fat, pasty
Example Output: sugars

Example Input: Category: guitar part 
Words: frustrated, amp, string, fret, headstock
Example Output: frustrated

Example Input: Category: personal characteristic 
Words: cool, unruffled, funny, chill, ethical
Example Output:
chill