You cannot windsurf when the air is completely still.
Examples of windsurf
windsurf
Tourists come here to visit the city's many beaches, and to windsurf and sail.
From the nzherald.co.nz
Hayward grew up in Falmouth, Maine, where he learned to windsurf in the Atlantic Ocean.
From the timesunion.com
Beck's 25-year record as Olympic windsurf coach is a remarkable one.
From the nzherald.co.nz
My windsurf buddies and I sat on the beach while the kiters went off.
From the washingtonpost.com
Some have ventured out to windsurf, fish or check the Gulf, he said.
From the heraldtribune.com
Marty's windsurf from Dakar, Senegal, to French Guiana took 37 days.
From the time.com
Pichilemu is the main beach in O'Higgins Region, known as a place to surf, windsurf and funboard.
From the en.wikipedia.org
One man was caught on camera using a skateboard and an umbrella in an attempt to windsurf on dry land.
From the orlandosentinel.com
Instead of running laps, he would teach his son to windsurf.
From the cnn.com
More examples
Ride standing on a surfboard with an attached sail, on water; "You cannot windsurf when the air is completely still"
(Windsurfers) Windsurfing is a surface water sport that combines elements of surfing and sailing. It consists of a board usually two to four meters long, powered by the orthogonal effect of the wind on a sail. ...
(windsurfing) A marine sport in which one stands on a floating board (typically 2 - 3 meters in length) to which a sail is attached. The board is steered by tilting the sail or banking the board. Some windsurfers use large waves to perform jumps and other stunts