Anticyclonic shear

From Glossary of Meteorology

anticyclonic shear

Horizontal wind shear of such a nature that it contributes to the anticyclonic vorticity of the flow; that is, it tends to produce anticyclonic rotation of the individual air particles along the line of flow.

In the Northern Hemisphere, anticyclonic shear is present if (when one faces downwind) the wind speed decreases from left to right across the direction of flow; the opposite is true in the Southern Hemisphere.
Compare cyclonic shear.