What is "unhorsing"

Usage examples of "unhorsing".

Yet he acquitted himself well, unhorsing Horas Redwyne in his first joust and one of the Freys in his second.

Robert had been jesting with Jon and old Lord Hunter as the prince circled the field after unhorsing Ser Barristan in the final tilt to claim the champion's crown.

We're far more likely to encounter Guardsmen than we are Chandim -but if we start unhorsing all these tin men with our minds, the noise is going to attract the Chandim like a beacon.