It could be a:
* Misspelling of a real word: There are many words that could be misspellings of "Wonaca," such as "Wanace," "Wonaco," "Wanaka" (a place in New Zealand), or even "Wonka" (from the book "Charlie and the Chocolate Factory").
* Made-up word: It could be a completely made-up word, in which case there is no "correct" spelling.
To help me determine the correct spelling, please provide more information:
* What is the context? Where did you see or hear the word "Wonaca"?
* What language is it from?
* Is there a definition or explanation for the word?
With more information, I can assist you in finding the correct spelling.