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: elements 
Words: let go, flame, inferno, fire, water

Answer: let go


Question: Category: animal 
Words: flutter, swim, ant, fly, bats

Answer: flutter


Question: Category: poker 
Words: pack, hearts, deck, queen, rudder

Answer:
rudder