not have the foggiest (idea)

成語所屬單字foggy

not have the foggiest (idea) — 慣用語

1. To have no knowledge or understanding about something.

1.慣用語
釋義

一無所知

To have no knowledge or understanding about something.

例句

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.