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: moral characteristic 
Words: light, unprejudiced, honorable, fair, unjust

SOLUTION: light

PROBLEM: Category: emotional status 
Words: downward, unhappy, down, shameful, disgusted

SOLUTION: downward

PROBLEM: Category: employment activity 
Words: fire, sack, combustion, let go, remove

SOLUTION:
combustion