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

Category: measurement unit 
Words: meter, inch, foot, heel, pound
heel

Category: poker 
Words: deck, gunwale, chips, hearts, queen

gunwale