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: flutter, swim, ant, fly, bats
flutter

Category: emotional status 
Words: worried, angry, jack, fret, emotional upsets
jack

Category: date status 
Words: current, prompt, delayed, blue, late

blue