For words that have only three letters, there is not any 4th letter. As an example with the word “increase”, there won't be any much more letters Later on and thus need to be the word "add". The word “addict” is from the BIP39 wordlist but you would've utilized “addi” https://bookmarkfox.com/story4499181/examine-this-report-on-bip39-passphrase