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: emotional display 
Words: buck, identity, culture, fawn, pester

Answer: buck


Question: Category: elements 
Words: pay, cool, combustion, air, fire

Answer: pay


Question: Category: emotional status 
Words: program, joyful, panicked, jealous, content

Answer:
program