[ krak ]
See synonyms for: crackcrackedcrackercracking on

verb (used without object)
  1. to break without complete separation of parts; become fissured: The plate cracked when I dropped it, but it was still usable.

  2. to break with a sudden, sharp sound: The branch cracked under the weight of the snow.

  1. to make a sudden, sharp sound in or as if in breaking; snap: The whip cracked.

  2. (of the voice) to break abruptly and discordantly, especially into an upper register, as because of weariness or emotion.

  3. to fail; give way: His confidence cracked under the strain.

  4. to succumb or break down, especially under severe psychological pressure, torture, or the like: They questioned him steadily for 24 hours before he finally cracked.

  5. Chemistry. to decompose as a result of being subjected to heat.

  6. Chiefly South Midland and Southern U.S. to brag; boast.

  7. Chiefly Scot. to chat; gossip.

verb (used with object)
  1. to cause to make a sudden sharp sound: The driver cracked the whip.

  2. to break without complete separation of parts; break into fissures.

  1. to break with a sudden, sharp sound: to crack walnuts.

  2. to strike and thereby make a sharp noise: The boxer cracked his opponent on the jaw.

  3. to induce or cause to be stricken with sorrow or emotion; affect deeply.

  4. to utter or tell: to crack jokes.

  5. to cause to make a cracking sound: to crack one's knuckles.

  6. to damage, weaken, etc.: The new evidence against him cracked his composure.

  7. to make mentally unsound.

  8. to make (the voice) harsh or unmanageable.

  9. to solve; decipher: to crack a murder case.

  10. Informal. to break into (a safe, vault, etc.).

  11. Chemistry. to subject to the process of cracking, as in the distillation of petroleum.

  12. Informal. to open and drink (a bottle of wine, liquor, beer, etc.).

  1. a break without complete separation of parts; fissure.

  2. a slight opening, as between boards in a floor or wall, or between a door and its doorpost.

  1. a sudden, sharp noise, as of something breaking.

  2. the snap of or as of a whip.

  3. a resounding blow: He received a terrific crack on the head when the branch fell.

  4. Informal. a witty or cutting remark; wisecrack.

  5. a break or change in the flow or tone of the voice.

  6. Informal. opportunity; chance; try: Give him first crack at the new job.

  7. a flaw or defect.

  8. Also called rock. Slang. pellet-size pieces of highly purified cocaine, prepared with other ingredients for smoking, and known to be especially potent and addicting.

  9. Masonry. check1 (def. 44).

  10. a mental defect or deficiency.

  11. a shot, as with a rifle: At the first crack, the deer fell.

  12. a moment; instant: He was on his feet again in a crack.

  13. Slang. a burglary, especially an instance of housebreaking.

  14. Chiefly British. a person or thing that excels in some respect.

  15. Slang: Vulgar. the vulva.

  16. Chiefly Scot. conversation; chat.

  17. British Dialect. boasting; braggadocio.

  18. Archaic. a burglar.

  1. first-rate; excellent: a crack shot.

  1. with a cracking sound.

Verb Phrases
  1. crack down, to take severe or stern measures, especially in enforcing obedience to laws or regulations: The police are starting to crack down on local drug dealers.

  2. crack off, to cause (a piece of hot glass) to fall from a blowpipe or punty.

  1. crack on, Nautical.

    • (of a sailing vessel) to sail in high winds under sails that would normally be furled.

    • (of a power vessel) to advance at full speed in heavy weather.

  2. crack up, Informal.

    • to suffer a mental or emotional breakdown.

    • to crash, as in an automobile or airplane: He skidded into the telephone pole and cracked up.

    • to wreck an automobile, airplane, or other vehicle.

    • to laugh or to cause to laugh unrestrainedly: That story about the revolving door really cracked me up. Ed cracked up, too, when he heard it.

Idioms about crack

  1. crack a book, Informal. to open a book in order to study or read: He hardly ever cracked a book.

  2. crack a smile, Informal. to smile.

  1. crack wise, Slang. to wisecrack: We tried to be serious, but he was always cracking wise.

  2. fall through the cracks, to be overlooked, missed, or neglected: In any inspection process some defective materials will fall through the cracks.: Also slip between the cracks.

  3. get cracking, Informal.

    • to begin moving or working; start: Let's get cracking on these dirty dishes!

    • to work or move more quickly.

Origin of crack

First recorded before 1000; Middle English crak (noun), crak(k)en (verb), Old English cracian “to resound”; cognate with German krachen, Dutch kraken (verb), and German Krach, Dutch krak (noun)

Other words from crack

  • crack·a·ble, adjective
  • crackless, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use crack in a sentence

British Dictionary definitions for crack


/ (kræk) /

  1. to break or cause to break without complete separation of the parts: the vase was cracked but unbroken

  2. to break or cause to break with a sudden sharp sound; snap: to crack a nut

  1. to make or cause to make a sudden sharp sound: to crack a whip

  2. to cause (the voice) to change tone or become harsh or (of the voice) to change tone, esp to a higher register; break

  3. informal to fail or cause to fail

  4. to yield or cause to yield: to crack under torture

  5. (tr) to hit with a forceful or resounding blow

  6. (tr) to break into or force open: to crack a safe

  7. (tr) to solve or decipher (a code, problem, etc)

  8. (tr) informal to tell (a joke, etc)

  9. to break (a molecule) into smaller molecules or radicals by the action of heat, as in the distillation of petroleum

  10. (tr) to open (esp a bottle) for drinking: let's crack another bottle

  11. (intr) Scot and Northern English dialect to chat; gossip

  12. (tr) informal to achieve (esp in the phrase crack it)

  13. (tr) Australian informal to find or catch: to crack a wave in surfing

  14. crack a smile informal to break into a smile

  15. crack hardy or crack hearty Australian and NZ informal to disguise one's discomfort, etc; put on a bold front

  16. crack the whip informal to assert one's authority, esp to put people under pressure to work harder

  1. a sudden sharp noise

  2. a break or fracture without complete separation of the two parts: a crack in the window

  1. a narrow opening or fissure

  2. informal a resounding blow

  3. a physical or mental defect; flaw

  4. a moment or specific instant: the crack of day

  5. a broken or cracked tone of voice, as a boy's during puberty

  6. (often foll by at) informal an attempt; opportunity to try: he had a crack at the problem

  7. slang a gibe; wisecrack; joke

  8. slang a person that excels

  9. Scot and Northern English dialect a talk; chat

  10. slang a processed form of cocaine hydrochloride used as a stimulant. It is highly addictive

  11. Also: craic informal, mainly Irish fun; informal entertainment: the crack was great in here last night

  12. obsolete, slang a burglar or burglary

  13. crack of dawn

    • the very instant that the sun rises

    • very early in the morning

  14. a fair crack of the whip informal a fair chance or opportunity

  15. crack of doom doomsday; the end of the world; the Day of Judgment

  1. (prenominal) slang first-class; excellent: a crack shot

Origin of crack

Old English cracian; related to Old High German krahhōn, Dutch kraken, Sanskrit gárjati he roars

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Idioms and Phrases with crack


In addition to the idioms beginning with crack

  • crack a book
  • crack a bottle
  • crack a joke
  • crack a smile
  • crack down
  • cracked up
  • crack of dawn
  • crack the whip
  • crack up

also see:

  • by jove (cracky)
  • fall between the cracks
  • get cracking
  • hard nut to crack
  • have a crack at
  • make a crack
  • not all it's cracked up to be
  • paper over (the cracks)

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.