a. [ Pref. in- not + susceptible: cf. F. insusceptible. ] Not susceptible; not capable of being moved, affected, or impressed; that can not feel, receive, or admit; as, a limb insusceptible of pain; a heart insusceptible of pity; a mind insusceptible to flattery; new strains of bacteria insusceptible to penicillin. -- In`sus*cep`ti*bly adv. [ 1913 Webster ]