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: boxing terminology 
Words: ring, lifeline, jab, deck, knockout
Example Output: lifeline

Example Input: Category: construction 
Words: tackle, crane, digger, sandpiper, dump truck
Example Output: sandpiper

Example Input: Category: type of sandwich 
Words: lettuce, grilled cheese, open-faced, clan, club
Example Output:
clan