Yes, ID is a valid Scrabble word!
the part of the mind in which innate instinctive impulses and primary processes are manifest
Synonyms: unconscious mind, mind, imagination, inner self, innermost self, self, inner man/woman, psyche, ego, superego
a Muslim festival, in particular Eid al-Fitr or Eid al-Adha
identification; identity
Synonyms: ID, papers, identity papers, identification papers, bona fides, documents, credentials