Is “Heresiarch” a Scrabble word?
Yes
HERESIARCH
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Heresiarch
/hɛˈɹiːzɪɑːk/
noun
1.The founder of a heresy, or a major ecclesiastical proponent of such a heresy.
Synonyms: arch-heretic