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: personal characteristic 
Words: ethical, tropical, unflappalbe, cool, optimist
Example Output: tropical

Example Input: Category: aesthetic characteristic 
Words: high quality, fine, attractive, alright, level
Example Output: alright

Example Input: Category: emotional status 
Words: left, emotional state, sad, emotional upsets, down
Example Output:
left