From Longman Dictionary of Contemporary Englishnot have the foggiest (idea)not have the foggiest (idea)spokenNOT KNOW to not know at all None of us had the foggiest idea about how to put the tent up. → foggy
Examples from the Corpus
not have the foggiest (idea)• I don't have the foggiest idea what his address is.• Before I go on, some of you may not have the foggiest what a fanzine is. 