Adverse yaw
From FlightSim
Adverse yaw happens because of the application of the ailerons in aircraft.
When the control column of an aircraft is moved to the right, the right aileron is deflected upwards, and the left aileron is deflected downwards. As a result the lift of the right wing is decreased and that of the left increased producing a roll to the right. Increased lift increases induced drag while decreased lift reduces it, so the drag of the left wing is increased and that of the right wing decreased. The effect of this is to yaw the aircraft to the left, in the wrong direction for the turn.
See also the Wikipedia entry adverse yaw.
