We don't have synonyms for zindiq yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are zendiq.
(n) :
(Islam, historical, derogatory) In medieval times, a person whose views or practices were considered contrary to Islamic dogma; a heretic or unbeliever, or one who practised heretical magic.
(n) :
(Islam, historical, derogatory) In medieval times, a person whose views or practices were considered contrary to Islamic dogma; a heretic or unbeliever, or one who practised heretical magic.