What is neutral steer?

Answer 1

Racing

In my opinion Neutral steer in a racing sense does not truly exist.

A car can not be set up to be truly neutral as the corner entry speed, the way the driver transitions from straight to the corner, throttle setting as the car exits the corner all change the over and under steer tendencies.

You can make a car more or less neutral for a particular driver, but the only truly neutral cornering I have ever seen was at a skid pad, this happened after a days work and the car over steered on entry and was neutral-ish while under steady speed around the circle.

Street cars

Neutral steer is the straight ahead on the motor way or freeway and requiring no steering input to track straight.

This is the ideal the manufacturers try to achieve but again not really possible.