The spelling of the word "hadst alibi" may seem confusing at first glance. However, it can be easily understood through its International Phonetic Alphabet (IPA) transcription. "Hadst" is pronounced as /hædst/, where the "a" represents the short "a" sound as in "cat" and the "d" and "st" combination indicates the word is in the second person singular past tense. "Alibi" is pronounced as /ælɪbaɪ/, where the first syllable is the same as "hadst" and the second syllable has the long "i" sound as in "eye". Together, "hadst alibi" means "you had an excuse or defense."