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: kitchenware 
Words: metal, glass, knifer, dish, cup
metal

Category: personal characteristic 
Words: cold, positive, calm, assured, cool
cold

Category: emotional status 
Words: string, nervous, fret, crying, concerned

string