Online heckler (5)

I believe the answer is:

troll

(Other definitions for troll that I've seen before include "Ugly character from Norse legend" , "Online pest" , "Fish - cave-elf" , "Ugly Norse dwarf" , "In Scandinavia, a mythical giant or dwarf" .)

I've seen this clue in The New York Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.