TASK DEFINITION: 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.
PROBLEM: Category: direction 
Words: down, opposite of up, sliding, forward, emotional state

SOLUTION: emotional state

PROBLEM: Category: outdoor sport activity 
Words: kayak, raft, fish, canyoning, dolphin

SOLUTION: dolphin

PROBLEM: Category: physical property 
Words: vitamin c, absorption, obese, heavy, fat

SOLUTION:
vitamin c