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.

Q: Category: moral characteristic 
Words: frank, concise, bun, matter of fact, fortitude

A: bun
****
Q: Category: weather 
Words: cold, luke, fair, mild, light

A: light
****
Q: Category: poker 
Words: pack, apron, deck, chips, cards

A:
apron
****