Plain English Meaning
The push and pull that moving air creates on the airplane as it flies through it. As the airplane slows down on approach, this push and pull weakens, which is why controls feel less responsive close to touchdown.
Full Definition
The aerodynamic effects produced by air flowing past and around an airplane in flight, including lift, drag, and the pressure forces acting on the wings, control surfaces, and airframe. During approach and landing, these forces influence how the airplane responds to control inputs, how it slows down, and how it settles onto the runway as airspeed decreases.