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: poker 
Words: fold, blind, deck, draw, box
Example Output: box

Example Input: Category: nutritional value 
Words: iron, heavy, vitamin c, fat, brittleness
Example Output: brittleness

Example Input: Category: window material 
Words: knife, plastic, spyhole, glass, wood
Example Output:
knife