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: acceptable, fine, hearing, jail time, probation
acceptable

Category: ocean 
Words: current, wave, whirlpool, sea, data sets
data sets

Category: social gathering 
Words: place, club, outing, lettuce, group

lettuce