in susceptible (adjective) insusceptible: insensitive
Sinonime: autonomous, chosen, deliberate, designful, discretional, elected, free, free-willed, freely, gratuitous, honorary, independent, intended, intentional, opted, optional, spontaneous, unasked, unbidden, unconstrained, unforced, unpaid, unprescribed, volitional, volunteer, willed, willful, wished, witting