A Clutch is a mechanical component which connects driving shaft to the driven shaft in order to start or stop driven shaft at will, without affecting the other. The clutch, as a result, serves as an uninterruptable connection between two rotating shafts. It is something that allows the high inertia load to be stated with small power.
The most popular use of the clutch is in the automotive industry, where it serves as a connection between the car’s engine and gearbox. It acts as a brake for the engine and this is the reason why improper shifting of gears can make your car stop. It slows down the engine so that wheels can catch up.