Greek 'without sensation' — and its etymological opposite is 'aesthetics,' the study of feeling beauty.
Insensitivity to pain, especially as artificially induced by the administration of gases or the injection of drugs before surgical operations.
From Greek 'anaisthēsia' (ἀναισθησία, insensibility, lack of feeling), from 'an-' (ἀν-, without, not) + 'aisthēsis' (αἴσθησις, feeling, sensation, perception), from 'aisthanesthai' (αἰσθάνεσθαι, to feel, to perceive), from PIE *h₂ew- (to perceive with the senses). The PIE root *h₂ew- carried the sense of apprehending reality directly through the body. Greek built 'aisthēsis' from it to mean specifically sensory perception — the raw data of experience