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.
--------
Question: Category: social gathering 
Words: club, bar, dance hall, discothek, roll

Answer: roll


Question: Category: physical property 
Words: obese, fat, vitamin c, heavy, thin

Answer: vitamin c


Question: Category: date status 
Words: prompt, water, current, dastards, detestings

Answer:
water