Lewis & Short

sēmĭ-ermis (sēmerm-, v. Liv. 27, 1, 15 Drak.; cf. semesus), e (in Liv.), and sēmĭ-ermus (sēmerm-), a, um (in Tac.), adj. [arma], half-armed, badly or indifferently armed: mille semermes per agros palati sunt, Liv. 39, 31: multitudo, id. 22, 50; 23, 5: exercitus, id. 25, 19; 27, 1 fin.: cum sex milibus semiermium, id. 28, 16; 30, 28; 31, 41; 40, 58: hosti et paucos ac semermos cogitanti, Tac. A. 1, 68; 3, 39 and 45.