C14: from Latin intestātus, from in-1 + testātus, from testārī to bear witness, make a will, from testis a witness
Word Origin and History for intestate
adj.
late 14c., from Old French intestat (13c.) and directly from Latin intestatus "having made no will," from in- "not" (see in- (1)) + testatus, past participle of testari "make a will, bear witness" (see testament). As a noun, "one who has not made out a will," from 1650s.