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: brittleness, protein, bulky, skinny, fat
Example Output: protein

Example Input: Category: emotional status 
Words: merchandise, angry, ecstatic, content, joyful
Example Output: merchandise

Example Input: Category: bird 
Words: parrot, hummingbird, swallow, crane, steam roller
Example Output:
steam roller