"Beautiful grey dress."
Translation:Gaun abu-abu cantik.
As far as I know "cantik" is to say beautiful to living things like girl/woman/cute animals. Otherwise 'handsome' is to boy/man. Ex: Dia cantik sekali hari ini (She is very beautiful today)
Indah means beautiful too in English. But it used for something beautiful places/sceneries (non living things) like beach/mountain. Ex: Pantai ini indah sekali (The beach is very beautiful).
For flowers (living thing) sometimes we can use both indah and cantik. Ex: Wah, bunga ini indah/cantik sekali. (Aww, these flowers are beautiful)