crack

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.

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. check.

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.

crack on

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

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

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 up

1. to suffer a mental or emotional breakdown.

2. to crash, as in an automobile or airplane.

   He skidded into the telephone pole and cracked up.

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

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

to break or cause to break without complete separation of the parts

the vase was cracked but unbroken

to break or cause to break with a sudden sharp sound; snap

to crack a nut

to make or cause to make a sudden sharp sound

to crack a whip

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

informal to fail or cause to fail

to yield or cause to yield

to crack under torture

(tr) to hit with a forceful or resounding blow

(tr) to break into or force open

to crack a safe

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

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

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

(tr) to open (esp a bottle) for drinking

let's crack another bottle

dialect (intr) to chat; gossip

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

informal (tr) to find or catch

to crack a wave in surfing

informal to break into a smile

informal to disguise one's discomfort, etc; put on a bold front

informal to assert one's authority, esp to put people under pressure to work harder

a sudden sharp noise

a break or fracture without complete separation of the two parts

a crack in the window

a narrow opening or fissure

informal a resounding blow

a physical or mental defect; flaw

a moment or specific instant

the crack of day

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

informal (often foll by at) an attempt; opportunity to try

he had a crack at the problem

slang a gibe; wisecrack; joke

slang a person that excels

dialect a talk; chat

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

Also: craic.  informal fun; informal entertainment

the crack was great in here last night

obsolete a burglar or burglary

1. the very instant that the sun rises

2. very early in the morning

informal a fair chance or opportunity

doomsday; the end of the world; the Day of Judgment