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

Answer: melancholy


Question: Category: bird 
Words: flamingo, crane, neck, ostrich, davit

Answer: davit


Question: Category: animals 
Words: jog, duck, ostrich, pig, horse

Answer:
jog