For words that only have three letters, there is not any 4th letter. Such as with the word “include”, there are no additional letters afterwards and thus have to be the word "incorporate". The word “addict” is inside the BIP39 wordlist but you would've applied “addi” for “addict”. This information https://bookmarkspring.com/story13914897/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator