Yes, LINEAMENT is a Scrabble word!

Letter values in Scrabble US: L 1, I 1, N 1, E 1, A 1, M 3, E 1, N 1, T 1.

Is it a valid word?

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

a characteristic property that defines the apparent individual nature of something
the characteristic parts of a person's face: eyes and nose and mouth and chin