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: animals 
Words: duck, jog, cat, pig, mallet
Example Output: jog

Example Input: Category: construction 
Words: excavator, steam roller, concrete pourer, swallow, crane
Example Output: swallow

Example Input: Category: emotional status 
Words: thing, fearful, jealous, content, disappointed
Example Output:
thing