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: bird 
Words: winch, swallow, winch, crane, parrot
winch

Category: physical property 
Words: bulky, angular momentum, pasty, fat, big
big

Category: secretary duty 
Words: firewall, support, fax, make coffee, file

firewall