This term is often described as front-end push – you will often hear NASCAR
drivers in the US talk about their car “pushing” – but the rest of the world
calls it understeer.
It occurs when the front tyres lose traction in a corner, so the car has a
tendency to want to steer straight ahead, causing it to run wider than where
you are steering.
You counter it instinctively by simply backing off the accelerator, so most
cars are designed to understeer at least slightly.
The opposite is oversteer, which is when the rear wheels slide out – this can
be fun, but requires skilled driving to control.