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: comfortable, money, fine, prison, jail time
comfortable

Category: physical activity 
Words: summer, roll, plummet, fall, exercise
summer

Category: poker 
Words: head, fold, deck, suits, joker

head