For words that only have three letters, there is no 4th letter. By way of example with the word “incorporate”, there won't be any far more letters Later on and therefore have to be the word "increase". The word “addict” is during the BIP39 wordlist however you would have made https://other-space.uncrn.co/blog/bip39-word-list-explained-your-necessary-resource-for-creating-secure-wallets-in-the-copyright-room/