gib ‧ ber /ˈdʒɪbə $ -ər/ BrE AmE verb [intransitive]
[ Date: 1600-1700 ; Origin: From the sound ]
to speak quickly in a way that is difficult to understand, especially because you are very frightened or shocked ⇨ jabber
gibber with
‘It was her,’ said Ruth, gibbering with fear.
—gibbering adjective British English :
a gibbering wreck (=someone who is very shocked or frightened)