Yes, PROGRESSIVE is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, O 1, G 2, R 1, E 1, S 1, S 1, I 1, V 4, E 1.

Is it a valid word?

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

a tense of verbs used in describing action that is on-going
a person who favors a political philosophy of progress and reform and the protection of civil liberties

favoring or promoting progress
favoring or promoting reform (often by government action)
(of taxes) adjusted so that the rate increases as the amount of income increases
gradually advancing in extent
(of a card game or a dance) involving a series of sections for which the participants successively change place or relative position
advancing in severity

Also: progressive tense, imperfect tense, continuous tense, reform-minded.