IPA: /ɪˌrɛvəkəˈbɪləti/
KK: /ɪˌrɛvəkəˈbɪlɪti/
The quality or state of being unable to be changed or reversed.
The irrevocability of her decision meant that there was no turning back.
Irrevocability → It is formed from "in-" (meaning not), "revocare" (meaning to call back or revoke), and "-ability" (meaning the quality of being able to). The word "irrevocability" means the quality of being unable to be called back or revoked.
Think of 'not' ('in-') being able to 'call back' ('revocare') something, which helps you remember that 'irrevocability' means something cannot be undone.