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: ocean 
Words: up to the moment, tide, current, jetstream, brine
Example Output: up to the moment

Example Input: Category: boats 
Words: hull, deck, rudder, check, lifeline
Example Output: check

Example Input: Category: corporate 
Words: firm, llc, amalgamated, tough, united
Example Output:
tough