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: corporate 
Words: solid, sustainability, streamline, firm, private

Answer: solid


Question: Category: fried food 
Words: apple, whittle, dumpling, fritter, pie

Answer: whittle


Question: Category: outdoor sport activity 
Words: swim, wrestle, fish, canyoning, horse

Answer:
horse