For words that only have three letters, there isn't any 4th letter. By way of example with the word “incorporate”, there aren't any a lot more letters afterwards and therefore should be the word "add". The word “addict” is in the BIP39 wordlist however , you might have employed “addi” https://directmysocial.com/story3693461/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39