Australian slang for rock, stone or pebble, or a small hardened rock shaped piece of dried mud or clay that shatters when you throw, bung or chuck it
against a wall leaving a small piece stuck to said wall with the remainder being
obliterated. Originating in the Gippsland region of Victoria, Australia in the late 1960's to early 1970's. Very often used in the town of Moe.
Hey Scott, bung a yonnie at
the wall mate.
I saw Danny chuck a yonnie at
the fence.
I bet that
window will break if you fling a yonnie at it.