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: neck, tackle, derrick, crane, steam roller
steam roller

Category: baby animals 
Words: bambi, cub, doe, lust, fawn
lust

Category: construction 
Words: windlass, dump truck, swift, winch, crane

swift