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: animal 
Words: bus, leap, spider, run, fly

SOLUTION: bus

PROBLEM: Category: type of rigidity 
Words: solid, leverage, hard, unbending, firm

SOLUTION: leverage

PROBLEM: Category: emotional status 
Words: down, unhappy, downward, remorseful, miserable

SOLUTION:
downward