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: animal 
Words: train, fly, jump, leap, grasshopper
train

Category: type of sandwich 
Words: hoagie, burger, hamburger, club, discothek
discothek

Category: widespread 
Words: captain, regular, universal, boring, general

captain