rack one's brain

Meaning

Verb

• To struggle to think of or remember something.

Origin

• Combination of rack, and brain, thus meaning “to cause the mind extreme discomfort”.
• Variants include rack one's wit (1583) and rack one's memory,{{cite-web
• |title=Wrack or rack?
• |url=http://www.worldwidewords.org/qa/qa-wra1.htm
• |author=Michael Quinion
• |date=2011-11-19
• |site=World Wide Words
• as well as cudgel one's brain / cudgel one's brains.