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: ocean 
Words: signal, timely, brine, flow, current

Answer: timely


Question: Category: elements 
Words: ice, fire, burn, let go, combustion

Answer: let go


Question: Category: type of sandwich 
Words: bacon, club, convention, doorstep, grilled cheese

Answer:
convention