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: physical property 
Words: brittleness, protein, bulky, skinny, fat

SOLUTION: protein

PROBLEM: Category: window material 
Words: glass, spyhole, handle, coating, knive

SOLUTION: knive

PROBLEM: Category: animal 
Words: bird, fish, fly, jog, swim

SOLUTION:
jog