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: animal 
Words: stingray, horse, iguana, wrestle, fish

Answer: wrestle


Question: Category: employment activity 
Words: recruit, replace, sack, heat, fire

Answer: heat


Question: Category: animal 
Words: bee, grasshopper, walk, fly, waggle

Answer:
walk