"fair dinkum" ?

Question

Where does this expression come from, and what does it mean ?

Thank u !

Answer 1

Dinkum or fair dinkum means "true", "the truth", "speaking the truth", and related meanings, depending on context and inflection. The derivation dinky-di means a 'true' or devoted Australian.
The words dinkum or dinky-di and phrases like 'true blue' are widely purported to be typical Australian sayings, however these sayings are more commonly used in jest or parody rather than as an authentic way of speaking.
In other words no one but Alf from Home and Away would actually use it in a sentence without being sarcastic!

Answer 2

Australian for "fair enough, then" or "all right, then."