windsurfing

Short definition from Wiktionary

Noun

1. 1
   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.

Verb

1. 1
   present participle and gerund of windsurf