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

Category: emotional status 
Words: merchandise, angry, ecstatic, content, joyful
merchandise

Category: police punishment 
Words: happy, penalty, jail time, prime, fine

happy