Open MonKorean → Settings → Account → Delete account. The app asks for confirmation once before it proceeds.
Deleting removes the following from the server: your email address, and all synced study progress including review cards, quiz results and personal settings.
Data already on your device is NOT removed by deleting the account. To clear that too, uninstall the app or use the local data reset in Settings.
Deletion cannot be undone. Signing up again with the same email address creates a new, empty account.
If you cannot sign in to delete the account yourself, email [email protected] from the account's own email address. I need the message to come from that address to confirm you own the account.