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: shady activities 
Words: invent, smuggled, smear, fudge, pie

A: pie
****
Q: Category: computers 
Words: hardware, sort mail, download, program, file

A: sort mail
****
Q: Category: police punishment 
Words: wispy, mad, flyaway, penalty, fine

A:
mad
****