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: outdoor sport activity 
Words: hiking, climbing, mice, fish, row
mice

Category: elements 
Words: let go, flame, inferno, fire, water
let go

Category: physical activity 
Words: bend, duck, goose, jog, crouch

goose