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: nutritional value 
Words: iron, heavy, vitamin c, fat, brittleness

SOLUTION: brittleness

PROBLEM: Category: outdoor sport activity 
Words: dog, swim, hike, hiking, fish

SOLUTION: dog

PROBLEM: Category: weather 
Words: warm, fair, luke, impartial, endure

SOLUTION:
impartial