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: guitar part 
Words: frustrated, amp, string, fret, headstock

Answer: frustrated


Question: Category: outdoor sport activity 
Words: kayak, raft, fish, canyoning, dolphin

Answer: dolphin


Question: Category: corporate 
Words: corporation, resistant, firm, llc, common

Answer:
resistant