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.
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Question: Category: type of sandwich 
Words: club, roll, doorstep, discothek, toast

Answer: discothek


Question: Category: outdoor sport activity 
Words: swim, wrestle, fish, canyoning, horse

Answer: horse


Question: Category: physical activity 
Words: jog, crouch, bow, duck, pig

Answer:
pig