Yes, DEIXISES is a Scrabble word!

Letter values in Scrabble US: D 2, E 1, I 1, X 8, I 1, S 1, E 1, S 1.

Is it a valid word?

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

the function of pointing or specifying from the perspective of a participant in an act of speech or writing; aspects of a communication whose interpretation depends on knowledge of the context in which the communication occurs