heckler vs mischief-maker

heckler and mischief-maker both are nouns.

Word	Noun	Adjective	Verb	Adverb
heckler	Yes	No	No	No
mischief-maker	Yes	No	No	No

As nouns, mischief-maker is a hypernym of heckler; that is, mischief-maker is a word with a broader meaning than heckler:

heckler: someone who tries to embarrass you with gibes and questions and objections
mischief-maker: someone who deliberately stirs up trouble

Other hypernyms of heckler include bad hat, trouble maker, troublemaker, troubler.

heckler (noun)	mischief-maker (noun)
someone who tries to embarrass you with gibes and questions and objections	someone who deliberately stirs up trouble