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: bird 
Words: concrete pourer, flamingo, egret, crane, duck

Answer: concrete pourer


Question: Category: animal 
Words: fish, iguana, canyoning, hamster, horse

Answer: canyoning


Question: Category: elements 
Words: blaze, hire, combustion, fire, burn

Answer:
hire