Verb
have the foggiest (third-person singular simple present has the foggiest, present participle having the foggiest, simple past and past participle had the foggiest)
(informal, usually with a negative) To know, understand or have a clue.
I'm sorry, I haven't the foggiest. You should ask someone else.
I don't think you have the foggiest notion of the contempt I have had for myself since the day I did that thing. Sterling Hayden