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: fat, vitamin c, area, brittleness, absorption

SOLUTION: vitamin c

PROBLEM: Category: window material 
Words: glass, coating, panel, spatula, lead

SOLUTION: spatula

PROBLEM: Category: emotional status 
Words: opposite of up, down, emotional upsets, miserable, unhappy

SOLUTION:
opposite of up