For words that have only three letters, there's no 4th letter. By way of example with the word “add”, there aren't any additional letters afterwards and therefore have to be the word "incorporate". The word “addict” is in the BIP39 wordlist however, you might have utilised “addi” for “addict”. Art https://hylistings.com/story19989851/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39