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: physical activity 
Words: trip, jump, fall, equinox, exercise
Example Output: equinox

Example Input: Category: type of sandwich 
Words: submarine, group, club, roll, grilled cheese
Example Output: group

Example Input: Category: bird 
Words: flamingo, crane, excavator, egret, tackle
Example Output:
excavator