IPA: /ˌɪrɪˈdiməbli/
KK: /ɪrɪˈdiməbli/
In a way that cannot be saved, improved, or corrected.
The situation seemed irredeemably lost after the final decision was made.
Irredeemably → It is formed from "in-" (meaning not), "redeem" (from Latin "redimere", meaning to buy back or recover), and "-ably" (meaning in a manner that can be). The word "irredeemably" means in a manner that cannot be bought back or recovered.
Think of 'not' ('in-') being able to 'recover' ('redeem') something, which helps you remember that 'irredeemably' means something that cannot be recovered.