Yes, SHOPWINDOW is a Scrabble word!

Letter values in Scrabble US: S 1, H 4, O 1, P 3, W 4, I 1, N 1, D 2, O 1, W 4.

Is it a valid word?

SHOPWINDOW is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a window of a store facing onto the street; used to display merchandise for sale in the store

Also: display window, shop window, show window.