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: boats 
Words: deck, gunwale, queen, lifeline, bridge
queen

Category: corporate 
Words: unyielding, firm, streamline, llc, private
unyielding

Category: construction 
Words: hoist, tackle, digger, excavator, crane

tackle