Thank you. Very interesting. Also Spanish and Italian, probably all the Romance Languages. http://etimologias.dechile.net/?oscuro#:~:text=La%20palabra%20oscuro%20viene%20del,queda%20a%20principio%20de%20palabra.
"The dark dress" isn't that common of a thing to say in english either, no?At least not if we are not talking about physical appearance (dark hair, dark eyes, dark skin etc.) Instead, greeks usually say
Tο σκουρόχρωμο φόρεμα - The dark-colored dress (when they don't specify the color) and
Το σκούρο πράσινο φόρεμα - The dark green dress (when they do specify the color).
I hope I helped. ^.^
Syntax is generally free in Greek but in sentences like this (the black dress, the wild duck, the handsome man etc) you have to add the adjective before the noun, unless you also add the article again as in το φόρεμα το πράσινο. In other cases you can mix ths syntax up if you want. For example you can say έχω μια δουλειά τέλεια!=I have a perfect job! but this syntax is used better when the sentence continues like in έχω μια δουλειά τέλεια που μου παρέχει όσα θέλω=I have a perfect job that provides me with all I want.