Is it ensure, insure, or assure?
1540s, as a medical term, from Middle French revulsion (16c.) or directly from Latin revulsionem (nominative revulsio) "a tearing off, act of pulling away," noun of action from past participle stem of revellere "to pull away," from re- "away" (see re-) + vellere "to tear, pull," from PIE *wel- "to tear, pull." The meaning "sudden reaction of disgust" is first attested 1816.
revulsion re·vul·sion (rĭ-vŭl'shən)
A sudden, strong change or reaction in feeling, especially a feeling of violent disgust or loathing.
Counterirritation used to reduce inflammation or increase the blood supply to an affected area.