For words that only have three letters, there isn't a 4th letter. For example with the word “increase”, there are no a lot more letters Later on and so have to be the word "include". The word “addict” is from the BIP39 wordlist however you would've utilized “addi” for “addict”. https://bookmarkforce.com/story18906250/top-latest-five-bip39-words-urban-news