To draw a blank is to search your memory and find nothing there. I drew a blank, drew a blank on the name, keep drawing a blank.
It also covers a search that turned up nothing, so police can draw a blank on an inquiry. The image is an old lottery where most tickets were blank and won nothing.
1phrasedraw a blankTo search your memory and find nothing there.
“I tried hard to remember her name, but I could only draw a blank.”
draw a blank is a failing.
Probably from an old lottery in which most tickets were blank and won nothing.
Probably from the idea of drawing of a blank (losing) ticket in an old-fashioned lottery.
Etymology from Wiktionary, CC BY-SA
Practised in Idioms