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: chocolate food 
Words: cake, fudge, rich, invent, cream

Answer: invent


Question: Category: guitar part 
Words: truss rod, fret, neck, bored, strap lock

Answer: bored


Question: Category: emotional status 
Words: concerned, bored, emotional, fret, output cord

Answer:
output cord