Origin: 1300–50; < Latin affirmāre, equivalent to af-af- + firmāre to make firm (see firm1); replacing Middle English a(f)fermen < Middle French afermer < Latin
early 14c., from O.Fr. afermer, from L. affirmare "to make steady, strengthen, corroborate," from ad- "to" + firmare "strengthen, make firm," from firmus "strong" (see firm (adj.)). Spelling refashioned 16c. on L. model.