[adj] impossible to reverse or be reversed; "irreversible momentum toward revolution" [adj] impossible to reverse or undo; "an irreversible decree"
irrevocable, irrevokable, permanent
reversible
beyond recall, beyond remedy, changeless, chronic, confirmed, constant, cureless, deep-dyed, deep-fixed, deep-rooted, deep-seated, deep-set, deep-settled, direct, dyed-in-the-wool, established, fast, final, fixed, gone, immediate, immedicable, immutable,