WordDictionary

Adjective:

• Excellent, first-rate, superior, top-notch.
• Highly trained and competent.

Noun:

• A narrow opening.
• A potent, relatively cheap, addictive variety of cocaine; often a rock, usually smoked through a crack-pipe.
• A sharply humorous comment; a wisecrack.
• A thin and usually jagged space opened in a previously solid material.
• computing A program, password or procedure designed to circumvent restrictions or usage limits on software.
• elsewhere throughout the North of the UK a meaningful chat.
• Scots|Liverpudlian Business/events
• informal An opportunity to attempt something.
• Internet slang Extremely silly, absurd or off-the-wall ideas or prose.
• informal|Liverpudlian good fun. (See usage note re Scots sense).
• onomatopoeia Any sharp sound.
• onomatopoeia The sharp sound made when solid material breaks.
• common in lowland Scotland and Ulster Conviviality; good conversation, chat, gossip, or humourous storytelling; good company.
• slang vagina.
• vulgar The space between the buttocks.

Verb:

• intransitive To form cracks.
• intransitive To make a cracking sound.
• of a pubescent boy's voice To alternate between high and low register in the process of eventually lowering.
• of a voice To change rapidly in register.
• intransitive To become debilitated by psychological pressure.
• intransitive To break apart under pressure.
• intransitive To make a sharply humorous comment.
• intransitive To yield under interrogation.
• chemistry|informal To break down (a complex molecule), especially with the application of heat: to pyrolyse.
• computing To circumvent software restrictions such as regional coding or time limits.
• informal To open a canned beverage, or any packaged drink or food.
• transitive To break open or crush to small pieces by impact or stress.
• transitive To cause to make a sharp sound.
• transitive To cause to yield under interrogation or other pressure. (''Figurative'')
• transitive To make a crack or cracks in.
• transitive To open slightly.
• transitive To overcome a security system or a component.
• Figurative, from cracking a nut.
• transitive To strike forcefully.
• transitive To tell (a joke).