Akkadian

padû - to spare, to release (CAD P 6, AHw. 808)

Derived words: pādû ‘forgiving’ (CDA 260); pidītu ‘pardon, alleviation’ (CAD P 359, AHw. 862); pīdu ‘pardon’ (CAD P 359, AHw. 862).

PS
*pdy - to buy out, to ransom, to redeem (EDA P N12)