exorcism UK /ˈɛk.sɔː.sɪ.zəm/US /ˈɛk.sɔɹˌsɪ.zəm/ noun1 •The ritual act of driving out evil spirits from persons, places or things that are possessed by them.Master Hume, we are therefore prouided: / will her Ladyship behold and heare our Exorcismes? — 1591 formsexorcisms