Yes, LOCKJAW is a Scrabble word!

Letter values in Scrabble US: L 1, O 1, C 3, K 5, J 8, A 1, W 4.

Is it a valid word?

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

an acute and serious infection of the central nervous system caused by bacterial infection of open wounds; spasms of the jaw and laryngeal muscles may occur during the late stages