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 property 
Words: obese, heavy, area, chunky, fat
Example Output: heavy

Example Input: Category: secretary duty 
Words: correspondence, schedule, answer calls, keys, file
Example Output: keys

Example Input: Category: chocolate food 
Words: cupcake, falsification, fudge, rich, molasses
Example Output:
falsification