Right, um... In general wind is the movement of air. Depending on its speed it can be a soft breeze or powerful enough to move big sailing ships across the oceans.
Wind, or Fūton, is also one of the five basic elemental nature transformations. Asuma told Naruto that creating wind chakra is like splitting the chakra into two and grinding them against each other to me them as sharp and thin as possible. Most wind techniques are offensive and cause precise alshing damage. Also, Fūton chakra can be channeled into blades to enhance their cutting ability.
Wind jutsus can be used in cojuction with water, increasing the detructive force of water techniques, or with fire, feeding the flames and increasing the size and damage of fire techniques. The last point also explaines why wind is weak against fire. On the other hand Fūton is superior to lightning, because air is a natural isolator, thus stopping the spreading of electricity.
Wind is a component of the kekkei genkai Ice release (+water) and the kekkei tōta Dust release (+fire and earth).