TASK DEFINITION: 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.
PROBLEM: Category: emotional display 
Words: buck, identity, culture, fawn, pester

SOLUTION: buck

PROBLEM: Category: boxing terminology 
Words: ring, lifeline, deck, punch, corner

SOLUTION: lifeline

PROBLEM: Category: direction 
Words: melancholy, down, opposite of up, up, flat

SOLUTION:
melancholy