곱다? I think you mean 귀엽다! Anyway, 예쁘다 means Pretty, 귀엽다 means Cute and 아름답다 means Beautiful.

Hi! I know it's an old question but I still hope my reply helps. I remember my 선생님 taught me that 곱다 is usually used when you are describing an elderly woman who is pretty/beautiful/lovely.