I agree with Bruce that it is not possible without context to determine the "better" adjective. However, I will point out one difference. If one says "the woman is gorgeous," the speaker is simply describing the woman. If one says "the woman is stunning," the speaker identifies the effect the woman has on those who see her, i.e. they are stunned. Presumably, the viewer is stunned by the woman's beauty, but this does not necessarily have to be the case. Ex: The woman was stunning in her phosphorescent dress. Or: The woman, at six-feet-8-inches-tall, was stunning.