noun, masculine/feminineplural: poderdantes
poderdante is masculine or feminine depending on context in Spanish.
grantor
“No obstante, el poderdante puede establecer en el poder el periodo de su vigencia, y transcurrido este, se entienden caducadas las facultades conferidas.” — However, the grantor may establish in the power the period of its validity, and after this, the powers conferred are understood to have expired.