Yes, NADIR is a Scrabble word!

Letter values in Scrabble US: N 1, A 1, D 2, I 1, R 1.

Is it a valid word?

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

an extreme state of adversity; the lowest point of anything
the point below the observer that is directly opposite the zenith on the imaginary sphere against which celestial bodies appear to be projected

NADIR was the Wordle answer on Sept. 13, 2025 (#1,547). Stuck on today’s? Use the Wordle helper.

Also: low-water mark.