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: boxing terminology 
Words: canvas, tko, deck, joker, fight
joker

Category: type of rigidity 
Words: unbending, unyielding, inflexible, firm, streamline
streamline

Category: widespread 
Words: typical, general, common, regular, cadet

cadet