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: corporate 
Words: unyielding, firm, streamline, llc, private
Example Output: unyielding

Example Input: Category: construction 
Words: excavator, steam roller, concrete pourer, swallow, crane
Example Output: swallow

Example Input: Category: animal 
Words: climbing, stingray, horse, fish, tiger
Example Output:
climbing