A counter hit is a counter-attack to an incoming loop
. Instead of waiting longer before hitting, the player will hit the ball earlier (close to the table), often when the ball is still rising after the first bounce (before the top of the bounce), to catch the other player out of position and give them less time to react or get back into position. This stroke relies on the incoming speed and spin to propel back very fast without actually applying very much force.
Some people apply the term "counter loop" to loops further back from the table (looping against the opponent's loop) which is very different from what is discussed here.