This is when you change gear and accelerate and nothing happens. You can hear the revs increasing (engine power) but there is no corresponding feel in the acceleration of the car.
You can feel a strong vibration through the car. This could indicate a worn engine mount (as all the ‘noise’ is transferred into the cars frame) or it could indicate that the clutch is worn and needs replacing – it’s always worth getting this inspected asap.
If you’re having trouble engaging any gears (especially 1st) it could indicate that the clutch is worn/sticking and needs to be inspected.
Harsh Feeling through Clutch pedal
This could indicate that the clutch is sticking, damaged and should be inspected as a precaution to casuing any additional damage to the vehicle.