Noun
any process that is not reversible
Source: WordNetWe are of the opinion that an important and irreversible process is taking place among the white population. Just as with the blacks, the whites, too, are currently overcoming a psychological barrier. Joe Slovo
From that moment on, there will be an irreversible process to separate Quebec from Canada. Jean Charest
Life is an irreversible process and for that reason its future can never be a repetition of the past. Walter Lippmann