TASK DEFINITION: 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.
PROBLEM: flap, glide, fly, train, bats

SOLUTION: bats

PROBLEM: air, fire, hire, ban, promote

SOLUTION: air

PROBLEM: unhappy, down, sliding, lower, flat

SOLUTION:
unhappy