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: physical activity 
Words: stoop, crouch, bow, duck, dog
dog

Category: moral characteristic 
Words: wiener, frank, integrity, loyalty, stern
wiener

Category: animal 
Words: train, fly, jump, leap, grasshopper

train