1A backwards turn or bend; a twist; the fact of being twisted or bent backwards.
2Originally: †the act of giving something back or in return (obsolete). Later: the action or an act of retorting an argument, charge, etc.
3Return for something done; retaliation. Now chiefly: (International Law) retaliation within the law by a state on another's subjects; an instance of this.
Early 17th century; earliest use found in Joshua Sylvester (d. 1618), poet and translator. From French rétorsion act of turning around, reversal, act of retorting, probably from Middle French retorquer to return, turn back, retort + -ion, after Middle French torsion. Compare post-classical Latin retortion-, retortio.