Yes, TAKEAWAY is a Scrabble word!

Letter values in Scrabble US: T 1, A 1, K 5, E 1, A 1, W 4, A 1, Y 4.

Is it a valid word?

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

prepared food that is intended to be eaten off of the premises
a concession made by a labor union to a company that is trying to lower its expenditures
the act of taking the ball or puck away from the team on the offense (as by the interception of a pass)

Also: takeout food.