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: police punishment 
Words: hearing, firstrate, alert, custody, fine
alert

Category: employment activity 
Words: fire, remove, praise, inferno, replace
inferno

Category: animal 
Words: cat, sea turtle, fish, stingray, hunt

hunt