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: hiking, stingray, shark, fish, tiger

SOLUTION: hiking

PROBLEM: swallow, heron, crane, flamingo, tackle

SOLUTION: tackle

PROBLEM: derrick, concrete pourer, steam roller, derrick, crane

SOLUTION:
derrick