TORMENTOR (Gr. basanistēs, torturer). This word occurs only in the NT (Matt.18.34 kjv), where the unforgiving debtor is delivered to tormentors, probably meaning the jailers (so niv).
). A word found in the KJV of Matthew 18:34
(RSV JAILER), referring to jailers whose job it was not only to keep debtors safe, but also to make them miserable until their debts were paid. Ordinarily, debtors were sold into slavery if they could not pay, but sometimes they were sent to jail until restitution was made.
International Standard Bible Encyclopedia (1915)
tor-men’-ter: the King James Version 2 Macc 7:29 for demios "belonging to the people," and so "public executioner," the Revised Version (British and American) "butcher." A term of utter contempt, whose force is lost in the King James Version. Also Mt 18:34 for basanistes, "torturer." Normally the bankrupt debtor was sold into slavery. But, apparently, in extreme cases (where concealment of assets was suspected?) the defaulter was sent to prison until restitution should be made. Probably the imprisonment itself was regarded as "torment" (as it doubtless was), and the "tormentors" need mean nothing more than jailers.