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: body part 
Words: inch, head, foot, ear, finger
Example Output: inch

Example Input: Category: animal 
Words: goat, stingray, tiger, hike, fish
Example Output: hike

Example Input: Category: emotional status 
Words: fret, truss rod, emotional upsets, sad, worried
Example Output:
truss rod