Definition of "oraculous"

If, Mrs Betty, I had not been used to your oughts, and to have my duty laid down to me by your oraculous wisdom, I should be apt to stare at the liberty of your speech.

1748, [Samuel Richardson], “Letter LXIII”, in Clarissa. Or, The History of a Young Lady: […], volumes (please specify |volume=I to VII), London: […] S[amuel] Richardson; […]