IPA: /ɪnˈɛf.ə.seɪ.bli/
KK: /ɪnˈɛfɪsəblɪ/
In a way that cannot be erased or removed; permanently.
The memories of that day are ineffaceably etched in my mind.
Ineffaceably → It is formed from "in-" (meaning not), "efface" (from Latin "effacere", meaning to erase or wipe out), and "-ably" (meaning in a manner that can be). The word "ineffaceably" means in a manner that cannot be erased or wiped out.
Think of something that cannot be 'erased' ('efface') and remember that 'ineffaceably' means it cannot be removed.