Is it ensure, insure, or assure?
late 14c., from Middle French absent (Old French ausent), from Latin absentem (nominative absens), present participle of abesse "be away from, be absent" (see absence). Related: Absently; absentness.
"to keep away" (from), c.1400, from Middle French absenter, from Late Latin absentare "cause to be away," from Latin absentem (see absent (adj.)). Related: Absented; absenting.
"in the absence of," 1944, principally from U.S. legal use, from absent (v.).