For words that have only three letters, there is no 4th letter. Such as with the word “increase”, there isn't any a lot more letters Later on and therefore should be the word "increase". The word “addict” is during the BIP39 wordlist but you would've employed “addi” for “addict”. BIP39 https://mylittlebookmark.com/story4420789/fascination-about-bip39-english-words