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: weather 
Words: raining, sunny, fair, ghostly, windy
Example Output: ghostly

Example Input: Category: type of rigidity 
Words: unbending, unyielding, inflexible, firm, streamline
Example Output: streamline

Example Input: Category: outdoor sport activity 
Words: sea turtle, swim, fish, hunt, row
Example Output:
sea turtle