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: weather 
Words: raining, sunny, fair, ghostly, windy

Answer: ghostly


Question: Category: emotional status 
Words: downward, unhappy, down, shameful, disgusted

Answer: downward


Question: Category: corporate 
Words: streamline, common, firm, resistant, united

Answer:
resistant