instruction:
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.
question:
Category: type of rigidity 
Words: rigged, firm, unyielding, streamline, taut
answer:
streamline


question:
Category: direction 
Words: down, lower, emotional upsets, below, falling
answer:
emotional upsets


question:
Category: window material 
Words: plastic, glass, frame, plate, vinyl
answer:

plate