Lord (only) knows (what, where, why, etc.)…

idiomPart ofknow

Lord (only) knows (what, where, why, etc.)… — idiom

1. Used to say that you do not know the answer to something.

1.idiom
Definition

Used to say that you do not know the answer to something.

Example

Lord only knows where he left his keys.

Why did she say that? Lord knows!