To throw or toss something carelessly or clumsily. He bunged the keys onto the table without looking.
To close or block something, especially a hole or opening. She bunged up the pipe to stop the leak.
British informal: to put or place something somewhere quickly or casually. Just bung the leftovers in the fridge.
British informal: to give someone a bribe or illicit payment. They bunged the official a few quid to speed up the paperwork.