Given a set of five words, generate the word from the set that does not belong (i.e. is the least relevant) with the other words. Words are separated by commas.

[EX Q]: firm, tough, solid, hard, streamline
[EX A]: streamline

[EX Q]: fighter, boring, popular, standard, general
[EX A]: fighter

[EX Q]: fire, earth, instruct, combustion, flame
[EX A]:
instruct