Lewis & Short

dĕ-armo, āvi, ātum, l, v. a.

  1. I. Aliquem, to disarm (except in particip., late Lat. for armis spoliare): dearmatus exercitus, Liv. 4. 10, 7.
  2. II. Aliquid, to deprive of power, blunt: pharetram expilet, sagittas dearmet, App. M. 5, p. 172, 25.