unwelcome person, persona non grata - a person who for some reason is not wanted or welcome

agitator, fomenter - one who agitates; a political troublemaker

disturber - a troubler who disquiets or interferes with peace and quiet; someone who causes disorder and commotion

badgerer, heckler - someone who tries to embarrass you with gibes and questions and objections

hellion, devil, heller - a rowdy or mischievous person (usually a young man); "he chased the young hellions out of his yard"

hellhound - a very evil man

inciter, instigant, instigator, provoker, firebrand - someone who deliberately foments trouble; "she was the instigator of their quarrel"

blusterer, loudmouth - a person who causes trouble by speaking indiscreetly

cut-up, hoaxer, practical joker, prankster, tricker, trickster - someone who plays practical jokes on others

rioter - troublemaker who participates in a violent disturbance of the peace; someone who rises up against the constituted authority