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: computers 
Words: hardware, sort mail, download, program, file
sort mail

Category: aesthetic characteristic 
Words: mild, fair, texture, even, milky
mild

Category: aesthetic characteristic 
Words: tone, fair, ghostly, even, endure

endure