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Glite Dictionary
to rack one's brain

to rack one's brain

13 5.8
Think very hard to remember something or solve a problem
  • idiom
  • Informal
: comerse la cabeza
  • She racked her brain to remember where she had left her keys.
  • racked my brain trying
  • racked my brain trying to remember
  • racked my brain to figure

Examples

  • I racked my brain for any question I could think of to ask Stanley about next week's homework.

    Fiction book (1997)

  • Jane racked her brains to recall the last time she had a proper conversation with Nick.

    Fiction book (2000)

  • Then the friend would shut up and rack his brains for a different subject.

    Fiction book (1998)

  • I racked my brain over it.

    Gun Shy (2000)

  • I keep racking my brain, going over these unsolved murder cases.

    Bicycle Dreams (2009)

  • Marie felt she had made a horrible mistake and racked her brains about how she could make things right again.

    Fiction book (1995)

  • I've been racking my brain ever since we left the diner.

    Paranormal Whacktivity (2013)

  • Andrea, I'm racking my brain trying to remember, but I think we might have known each other.

    Blog text (33)

  • I've been racking my brains, but I can't think of anything else.

    Fiction book (1996)

  • Now, as the carriage sped through the spring streets towards Kensington, she racked her brains for a credible tale.

    Fiction book (1990)

Synonyms

to beat my brain
vsto rack one's brain
  • Informal
1 8.2

To think very hard to remember something or to solve a problem

is the same heavy mental effort but phrased in a different idiom
to cudgel my brain
vsto rack one's brain
  • Archaic
9.1

To think very hard to remember or solve a problem

is about intense effort to recall or solve rather than light thought
to bend my brain
vsto rack one's brain
  • Informal
8.8

To think very hard about something until you feel confused

focuses on hard remembering or solving, not creative or confusing thought

Antonyms

to forget
∞ 1.0

Not remember something you should remember

How Hard

to rack one's brain
  • Informal
13 5.8
to ponder
134 4.3
to concentrate
561 3.4
to consider
∞ 1.1
to think
∞ 1.0

Surface Forms

rack one's brain infinitive
racked one's brain past
racked one's brain past participle
racking one's brain present participle
racks one's brain third person singular

Morphology

rack + one + brain

The sense follows a visible metaphor: 'rack' (to strain/torment) + 'brain' (mind) yields 'strain the mind', so a learner who knows the constituents can plausibly infer 'think very hard/try to remember.' However, the use of 'rack' in this figurative sense is somewhat literary/idiomatic and requires a metaphoric mapping rather than straightforward composition, so it is not fully predictable without prior exposure.

Etymology

Rack one's brain may come from an old tool called a rack, used to pull and stretch a person's body. Imagine stretching your brain to pull out an answer. That's why the phrase means 'to think very hard' or 'to try to remember'.