Yes, REINSURANCE is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, I 1, N 1, S 1, U 1, R 1, A 1, N 1, C 3, E 1.

Is it a valid word?

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

sharing the risk by insurance companies; part or all of the insurer's risk is assumed by other companies in return for part of the premium paid by the insured