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: animal 
Words: flutter, fly, bats, eagle, pounce
Example Output: flutter

Example Input: Category: window material 
Words: glass, coating, panel, spatula, lead
Example Output: spatula

Example Input: Category: aesthetic characteristic 
Words: fine, pretty, calm, high quality, exquisite
Example Output:
calm