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: geographical property 
Words: studio, hill, flat, even, horizontal

Answer: studio


Question: Category: direction 
Words: below, backward, melancholy, down, ground

Answer: melancholy


Question: Category: moral characteristic 
Words: raining, honorable, fair, fine, trustworthy

Answer:
raining