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.

Category: police punishment 
Words: prime, penalty, fine, mad, arrest
mad

Category: police punishment 
Words: classy, probation, custody, fine, flyaway
classy

Category: outdoor sport activity 
Words: mice, swim, camp, fish, wrestle

mice