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.

Category: outdoor sport activity 
Words: wrestle, fish, iguana, hiking, hunt
iguana

Category: outdoor sport activity 
Words: dog, swim, hike, hiking, fish
dog

Category: corporate 
Words: private, firm, solid, streamline, synergy

solid