crack up


verb (used without object)
to break without complete separation of parts; become fissured: The plate cracked when I dropped it, but it was still usable.
to break with a sudden, sharp sound: The branch cracked under the weight of the snow.
to make a sudden, sharp sound in or as if in breaking; snap: The whip cracked.
(of the voice) to break abruptly and discordantly, especially into an upper register, as because of weariness or emotion.
to fail; give way: His confidence cracked under the strain.
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.
Chemistry. to decompose as a result of being subjected to heat.
Chiefly South Midland and Southern U.S. to brag; boast.
Chiefly Scot. to chat; gossip.
verb (used with object)
to cause to make a sudden sharp sound: The driver cracked the whip.
to break without complete separation of parts; break into fissures.
to break with a sudden, sharp sound: to crack walnuts.
to strike and thereby make a sharp noise: The boxer cracked his opponent on the jaw.
to induce or cause to be stricken with sorrow or emotion; affect deeply.
to utter or tell: to crack jokes.
to cause to make a cracking sound: to crack one's knuckles.
to damage, weaken, etc.: The new evidence against him cracked his composure.
to make mentally unsound.
to make (the voice) harsh or unmanageable.
to solve; decipher: to crack a murder case.
Informal. to break into (a safe, vault, etc.).
Chemistry. to subject to the process of cracking, as in the distillation of petroleum.
Informal. to open and drink (a bottle of wine, liquor, beer, etc.).
a break without complete separation of parts; fissure.
a slight opening, as between boards in a floor or wall, or between a door and its doorpost.
a sudden, sharp noise, as of something breaking.
the snap of or as of a whip.
a resounding blow: He received a terrific crack on the head when the branch fell.
Informal. a witty or cutting remark; wisecrack.
a break or change in the flow or tone of the voice.
Informal. opportunity; chance; try: Give him first crack at the new job.
a flaw or defect.
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.
Masonry. check1 ( def 41 ).
a mental defect or deficiency.
a shot, as with a rifle: At the first crack, the deer fell.
a moment; instant: He was on his feet again in a crack.
Slang. a burglary, especially an instance of housebreaking.
Chiefly British. a person or thing that excels in some respect.
Slang: Vulgar. the vulva.
Chiefly Scot. conversation; chat.
British Dialect. boasting; braggadocio.
Archaic. a burglar.
first-rate; excellent: a crack shot.
with a cracking sound.
Verb phrases
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.
crack off, to cause (a piece of hot glass) to fall from a blowpipe or punty.
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.
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.
crack a book, Informal. to open a book in order to study or read: He hardly ever cracked a book.
crack a smile, Informal. to smile.
crack wise, Slang. to wisecrack: We tried to be serious, but he was always cracking wise.
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.
get cracking, Informal.
to begin moving or working; start: Let's get cracking on these dirty dishes!
to work or move more quickly.

before 1000; Middle English crak(k)en (v.), crak (noun), Old English cracian to resound; akin to German krachen, Dutch kraken (v.), and German Krach, Dutch krak (noun)

crackable, adjective
crackless, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To crack up
World English Dictionary
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
3.  to make or cause to make a sudden sharp sound: to crack a whip
4.  to cause (the voice) to change tone or become harsh or (of the voice) to change tone, esp to a higher register; break
5.  informal to fail or cause to fail
6.  to yield or cause to yield: to crack under torture
7.  (tr) to hit with a forceful or resounding blow
8.  (tr) to break into or force open: to crack a safe
9.  (tr) to solve or decipher (a code, problem, etc)
10.  informal (tr) to tell (a joke, etc)
11.  to break (a molecule) into smaller molecules or radicals by the action of heat, as in the distillation of petroleum
12.  (tr) to open (esp a bottle) for drinking: let's crack another bottle
13.  dialect (Scot), (Northern English) (intr) to chat; gossip
14.  informal (tr) to achieve (esp in the phrase crack it)
15.  informal (Austral) (tr) to find or catch: to crack a wave in surfing
16.  informal crack a smile to break into a smile
17.  informal (Austral), (NZ) crack hardy, crack hearty to disguise one's discomfort, etc; put on a bold front
18.  informal crack the whip to assert one's authority, esp to put people under pressure to work harder
19.  a sudden sharp noise
20.  a break or fracture without complete separation of the two parts: a crack in the window
21.  a narrow opening or fissure
22.  informal a resounding blow
23.  a physical or mental defect; flaw
24.  a moment or specific instant: the crack of day
25.  a broken or cracked tone of voice, as a boy's during puberty
26.  informal (often foll by at) an attempt; opportunity to try: he had a crack at the problem
27.  slang a gibe; wisecrack; joke
28.  slang a person that excels
29.  dialect (Scot), (Northern English) a talk; chat
30.  slang a processed form of cocaine hydrochloride used as a stimulant. It is highly addictive
31.  informal chiefly (Irish) Also: craic fun; informal entertainment: the crack was great in here last night
32.  obsolete, slang a burglar or burglary
33.  crack of dawn
 a.  the very instant that the sun rises
 b.  very early in the morning
34.  informal a fair crack of the whip a fair chance or opportunity
35.  crack of doom doomsday; the end of the world; the Day of Judgment
36.  slang (prenominal) first-class; excellent: a crack shot
[Old English cracian; related to Old High German krahhōn, Dutch kraken, Sanskrit gárjati he roars]

crack up
1.  (intr) to break into pieces
2.  informal (intr) to undergo a physical or mental breakdown
3.  informal (tr) to present or report, esp in glowing terms: it's not all it's cracked up to be
4.  informal chiefly (US), (Canadian) to laugh or cause to laugh uproariously or uncontrollably
5.  informal a physical or mental breakdown

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Word Origin & History

O.E. cracian "make a sharp noise," from P.Gmc. *krakojan, probably onomatopoeic. The noun meaning "split, opening," is 14c. Meaning "try, attempt" first attested 1836, probably a hunting metaphor, from slang sense of "fire a gun." Meaning "rock cocaine" is first attested 1985. Cracked "mentally unsound"
is 17c. (though the equivalent Gk. word was used in this sense by Aristophanes), while crack as in "top-notch, superior" is slang from 1793. Crackpot "pretentious, worthless person" dates from 1883. The superstition that it is bad luck to step on sidewalk cracks has been traced to c.1890.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Idioms & Phrases

crack up

  1. Suffer an emotional breakdown, become insane, as in He might crack up under the strain. This usage alludes to the result of cracking one's skull; from the early 1600s to crack alone was used in this way. [Slang; early 1900s]

  2. Damage or wreck a vehicle or vessel. For example, I'm always afraid that I'll crack up the car.

  3. Experience a crash, as in We cracked up on the freeway in the middle of the ice storm.

  4. Also, crack someone up. Burst or cause to burst out laughing, as in The audience cracked up, or That joke really cracked me up. [Slang; c. 1940] Also see break up, def. 6. All of these expressions derive from crack in the sense of "break into pieces" or "collapse," a usage dating from the late 1600s. Also see cracked up.

The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
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Idioms & Phrases
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