- superlative form of foggy: most foggy
- Moscow is the foggiest city I've ever been to.
- (usually used in the negative) Very unclear; only slightly known; very difficult to understand or begin.
- I don't have the foggiest idea how to get to Piccadilly Circus on the Tube.
- She wasn't going to get the foggiest notion about modern writing from those old books.
- He asked me where she was going and I said "I don't have the foggiest."