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: window material 
Words: glass, coating, panel, spatula, lead
spatula

Category: aesthetic characteristic 
Words: well, milky, variety, tone, fair
well

Category: animal 
Words: sea turtle, dolphin, horse, fish, kayak

kayak