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: nutritional value 
Words: vitamin c, salt, sugar, fat, big boned
big boned

Category: corporate 
Words: corporation, firm, synergy, tough, concerted
tough

Category: accomodation 
Words: elevation, level, round, flat, townhome

elevation