Yes, DEFLECTION is a Scrabble word!

Letter values in Scrabble US: D 2, E 1, F 4, L 1, E 1, C 3, T 1, I 1, O 1, N 1.

Is it a valid word?

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

a twist or aberration; especially a perverse or abnormal way of judging or acting
the amount by which a propagating wave is bent
the movement of the pointer or pen of a measuring instrument from its zero position
the property of being bent or deflected
a turning aside (of your course or attention or concern)