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: animal 
Words: stingray, horse, iguana, wrestle, fish
wrestle

Category: moral characteristic 
Words: concise, brash, integrity, cheese, frank
cheese

Category: outdoor sport activity 
Words: kayak, trap, hamster, fish, row

hamster