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: employment activity 
Words: fire, remove, praise, inferno, replace
Example Output: inferno

Example Input: Category: nutritional value 
Words: heavy, protein, fat, sugars, area
Example Output: area

Example Input: Category: measurement unit 
Words: ounce, ear, inch, foot, milimeter
Example Output:
ear