For words that only have three letters, there is not any 4th letter. As an example with the word “incorporate”, there aren't any much more letters Later on and thus needs to be the word "increase". The word “addict” is inside the BIP39 wordlist however , you would've made use https://thebookmarkplaza.com/story19533751/the-fact-about-bip39-seed-phrase-word-list-that-no-one-is-suggesting