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: up, descending, down, lower, melancholy

Answer: melancholy


Question: Category: secretary duty 
Words: errands, fax, file, type, ram

Answer: ram


Question: Category: boats 
Words: bow, stern, dock, tko, deck

Answer:
tko