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: scold, water, fire, praise, replace
Example Output: water

Example Input: Category: animal 
Words: pounce, fly, swim, walk, walk
Example Output: walk

Example Input: Category: bird 
Words: crane, hummingbird, dump truck, winch, mallet
Example Output:
dump truck