Yes, CORRUPTION is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, R 1, R 1, U 1, P 3, T 1, I 1, O 1, N 1.

Is it a valid word?

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

lack of integrity or honesty (especially susceptibility to bribery); use of a position of trust for dishonest gain
in a state of progressive putrefaction
decay of matter (as by rot or oxidation)
moral perversion; impairment of virtue and moral principles
destroying someone's (or some group's) honesty or loyalty; undermining moral integrity
inducement (as of a public official) by improper means (as bribery) to violate duty (as by commiting a felony)

Not playable in Scrabble US: PUTRIDNESS.