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: moral characteristic 
Words: frank, stern, bun, concise, precise
Example Output: bun

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

Example Input: Category: emotional status 
Words: disappointed, excited, ecstatic, activity, content
Example Output:
activity