early 14c., from O.Fr. amonester (12c.), from V.L. admonestare, from L. admonere "advise, remind," from ad- "to" + monere "advise, warn" (see
monitor). The -d- was restored on L. model. The ending was infl. by words in -ish (e.g. astonish). Related: Admonitory (1590s).