irrevocable
adj.describing something that cannot be changed, stopped, or taken back. Once you make an irrevocable decision, you cannot undo it.
adj.describing an action, decision, or state that is final and cannot be reversed or rescinded. Often used in legal or formal contexts to indicate a permanent commitment.
“The contract is irrevocable once you sign it.”
“The board of directors made an irrevocable decision to close the factory, ending decades of local employment.”
“The treaty established an irrevocable commitment to peace, ensuring that no future government could alter the terms without the unanimous consent of all signatories.”
“But the permanent and irrevocable death of Kirk’s son seems to be passed over remarkably casually.”
From Middle French irrévocable, from Latin irrevocabilis; equivalent to ir- + revoke + -able.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.