The word "haddest" is an archaic form of the word "had". It is used in the phrase "haddest in keeping", which means to possess or hold something in custody. The spelling of "haddest" is derived from the Middle English word "haddestu", which is the second person singular form of the verb "have". In IPA phonetic transcription, the pronunciation of "haddest" is /ˈhædɪst/. Although this spelling is no longer commonly used in modern English, it remains a valuable example of the evolution of the English language over time.