Definition

(Adjective) Wanting in mental or moral feeling; devoid of sensibility; unaffected, unmoved; unfeeling. (Of persons, or their qualities, actions, etc.)

In Context

“Beneath this polished exterior, one sensed, lived a man capable of insensate rage and unrestrained debauchery, a man who, even before arriving in the tropics, had cast off the ennobling bonds of civilization and honour.”

Alan Vanneman, Sherlock Holmes and the Giant Rat of Sumatra, 2002.