0 past simple and past participle of gibber
1 to speak quickly in a way that cannot be understood, usually when you are very frightened or confused:
As an adult (which was in fact rare, as nearly all changelings were thought to die in early childhood) it was disabled, gibbered instead of talked, and mistrusted people.
She gibbered at the sight of patients on stretchers with nurses walking beside them holding blood bottles in the air and going down open corridors between the buildings.