Clipping is a way of processing a sound signal which blocks any amplification of any input signal which exceeds a certain volume.

Amplification of the incoming signal below that clipping level is not affected.

Most hearing aids have clipping levels that can be controled by the person who sets up the hearing aid. It's one of the most basic features that hearing aids use to prevent very loud sounds from being amplified and possibly causing further damage to your hearing.

Clipping is often confused with compression, which is something else, altogether.