Apparently from poros (a kind of stone); to petrify, i.e. (figuratively) to indurate (render stupid or callous)blind, harden.
Textus Receptus Greek Text
epwrwqhsan Rom 11:7
epwrwqh 2 Cor 3:14
pepwrwken John 12:40
pepwrwmenhn Mark 8:17
pepwrwmenh Mark 6:52