Where did you find this name? Was it the name of a man or a woman?
Ciar,
Ciaran , Ciarmacc, and Ciarnat are names found in
Irish Names by
Donnchadh OCorrain &
Fidelma Maguire, but Ciarda is not found there. Somehow the -da ending doesn't look Gaelic to me. Ciardo, on the other hand, is an Italian pet form of
Riccardo (
Richard), and Ciarda could be the feminine form of that.