Definition of chiack in English:
verb[with object] (usually as noun chiacking) Australian & NZ
Jeer at or tease.
- He's going to make me spend a day out on Murderer's Camp and then chiack me about it
- Whenever he came to the town on the mail truck from Billabalong, they'd hang around him while he joked and chiacked, breaking into laughter at it all.
- I cut off both thoughts and gave the answer I had given my grinning, chiacking, companions.
mid 19th century: from British slang chihike, originally a costermonger's cry.