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: bird 
Words: hummingbird, tackle, crane, hoist, tackle
Example Output: tackle

Example Input: Category: animal 
Words: hamster, mice, fish, tiger, row
Example Output: row

Example Input: Category: emotional status 
Words: kind, down, ashamed, remorseful, downward
Example Output:
downward