Yes, MILITARISMS is a Scrabble word!

Letter values in Scrabble US: M 3, I 1, L 1, I 1, T 1, A 1, R 1, I 1, S 1, M 3, S 1.

Is it a valid word?

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

a political orientation of a people or a government to maintain a strong military force and to be prepared to use it aggressively to defend or promote national interests