The word "haddest alibi" comprises of two distinct words, "haddest" and "alibi." "Haddest" is the second-person singular form of "have" in the past tense. The IPA phonetic transcription for "haddest" is /ˈhædɪst/. "Alibi," on the other hand, refers to an excuse given to prove innocence in case of a crime or wrongdoing. The IPA phonetic transcription for "alibi" is /ˈæləbaɪ/. Therefore, "haddest alibi" refers to having a provable excuse or defense for a crime or wrongdoing.