What is Onya?
1.
The shortened form of "Good on you," a sarcastic form of thanks usually reserved for use when somebody does something particularly stupid.
Idiot: "Oh no, I think the principal just saw us..."
Someone Else: "Onya, dickhead! You were supposed to look out!"
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2.
An
Sometimes used literally and sometimes used sarcastically.
Onya mate, that was the most stupid move I have ever seen.
Onya mate! that chick you picked up last night was no
bush pig she was totally hot!!
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3.
on you - short form.
"If you don't get off my porch i'm gonna throw up my chilimac onya"
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4.
Oh No! You Again?!?
typing ONYA is faster than Oh No! You AGAIN!?!?! And she would want to see her name in here.