Yes, DHAK is a Scrabble word!

Letter values in Scrabble US: D 2, H 4, A 1, K 5.

Is it a valid word?

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

East Indian tree bearing a profusion of intense vermilion velvet-textured blooms and yielding a yellow dye

Also: butea frondosa, butea monosperma.

Not playable in Scrabble US: PALAS.