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: activity 
Words: dally, goodbye, fritter, whittle, dumpling

Answer: dumpling


Question: Category: chocolate food 
Words: cake, fudge, rich, invent, cream

Answer: invent


Question: Category: card games 
Words: gin, uno, blackjack, tonic, slapjack

Answer:
tonic