For words that have only 3 letters, there isn't a 4th letter. Such as with the word “incorporate”, there isn't any additional letters Later on and thus needs to be the word "insert". The word “addict” is inside the BIP39 wordlist however , you would've utilised “addi” for “addict”. bip39-phrase.com https://bookmarkspy.com/story20301942/the-greatest-guide-to-seed-phrase-bip39