not have the foggiest (idea)
idiomPart offoggy
not have the foggiest (idea) — idiom
1. To have no knowledge or understanding about something.
1.idiom
Definition
To have no knowledge or understanding about something.
Example
Maya asked about the meeting time, but I didn't have the foggiest.
Does Brian have any clue where his keys are? He hasn't the foggiest idea.