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: military rank 
Words: general, fighter, normal, major, lieutenant

Answer: normal


Question: Category: window material 
Words: metal, handle, dish, glass, vinyl

Answer: dish


Question: Category: animal 
Words: fly, run, leap, bats, flap

Answer:
flap