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: consumer product 
Words: merchandise, happy, thing, content, service
happy

Category: poker 
Words: ring, deck, blind, cards, joker
ring

Category: moral characteristic 
Words: ghostly, impartial, well, fair, unjust

ghostly