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: type of rigidity 
Words: tough, taut, rough, amalgamated, firm

SOLUTION: amalgamated

PROBLEM: Category: window material 
Words: plastic, woodwork, glass, bowl, spyhole

SOLUTION: bowl

PROBLEM: Category: aesthetic characteristic 
Words: attractive, fine, dull, penalty, beautiful

SOLUTION:
penalty