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: boxing terminology 
Words: ring, lifeline, jab, deck, knockout
lifeline

Category: construction 
Words: hoist, crane, excavator, egret, derrick
egret

Category: nutritional value 
Words: protein, fat, capacitance, big, sugar

capacitance