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: weather 
Words: raining, cold, sunny, alright, fair
alright

Category: employment activity 
Words: recruit, replace, sack, heat, fire
heat

Category: type of sandwich 
Words: grilled cheese, cinema, hamburger, club, hero

cinema