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: window material 
Words: plastic, woodwork, glass, bowl, spyhole

Answer: bowl


Question: Category: mode of transportation 
Words: bus, fly, jog, beetle, drive

Answer: beetle


Question: Category: consumer product 
Words: activity, content, fearful, shop, substance

Answer:
fearful