For words that have only 3 letters, there's no 4th letter. Such as with the word “incorporate”, there are no additional letters afterwards and thus has to be the word "incorporate". The word “addict” is within the BIP39 wordlist however , you might have utilised “addi” for “addict”. BIP39 and https://bookmarkize.com/story19632817/the-5-second-trick-for-ledger-seed-phrase-bip39