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: emotional status 
Words: kind, down, sad, backward, emotionalities
Example Output: backward

Example Input: Category: police punishment 
Words: flyaway, jail time, ok, arrest, fine
Example Output: ok

Example Input: Category: animal 
Words: jump, cockroach, flap, fly, waggle
Example Output:
flap