Past tense 'chibbed'
Originally used by loan sharks in Glasgow, to chibb someone meant to
slash someones face, usually across the cheek with
two razor or Stanley
knife blades taped together with a coin between them.
This was done if they failed to repay their debt on time. Because this left two deep cuts with a thin strip of
skin between them, when they were sutured at the hospital it left a very visible raised scar, both as a warning to others what would happen if they failed to repay on time, and also to other loan sharks that the person could not be trusted.
This has now become used to describe an assault with a (usually blut) weapon, like a bottle or bat.