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: direction 
Words: down, backward, up, downward, shameful
shameful

Category: emotional status 
Words: down, emotional state, loveful, ashamed, flat
flat

Category: boats 
Words: chips, lifeline, stern, sail, deck

chips