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.

Category: bird 
Words: crane, sandpiper, hoist, windlass, goose
windlass

Category: animal 
Words: walk, flap, fish, fly, bats
flap

Category: police punishment 
Words: arrest, decent, prime, fine, penalty

decent