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: large, obese, fat, chunky, fiber
Example Output: fiber

Example Input: Category: employment activity 
Words: fire, remove, praise, inferno, replace
Example Output: inferno

Example Input: Category: personal characteristic 
Words: positive, cool, calm, level, icy
Example Output:
icy