For words that only have three letters, there is not any 4th letter. As an example with the word “include”, there are no a lot more letters afterwards and therefore has to be the word "incorporate". The word “addict” is from the BIP39 wordlist however, you would have made use https://loanbookmark.com/story19027826/invalid-bip39-phrase-things-to-know-before-you-buy