crack upverb/ˈkɹæk ˈʌp/

• 1

  To laugh.

  • It was hilarious. We were cracking up the whole time.
• 2

  To laugh.

  • The joke about the nuns in the bath cracked me up.
  • The joy of “Ticket to Paradise” comes not from its predictable plotting or razor-thin screenplay; it’s from watching them together, from observing how the sparks still fly, and (when the former flames get drunk and let their guards down, or during the end-credit outtakes) watching them crack each other up.
• 3

  slangTo laugh.

  • He's always cracking up at me about that.
• 4

  datedTo break.

  • She got through the war, but cracked up when her sister died.
  • All rather inhuman and undernourished, isn’t it? Well, that, children, is the true sign of cracking up.
• 5

  To break.

  • The university was really cracking up, losing faculty, students and donors, and it seemed like to go under.
  • My motorcycle cracked up before I arrived.
• 6

  To break.

  • I have to crack up that little clique.
• 7

  To break.

  • From all directions they came to the rescue, one predominant fear gripping their hearts: Fire! Someone had cracked-up. It was for this they sped. The flames that so frequently burst from a crashed airplane became an instantaneous cauldron; many a pilot has lived through the crash to die in the fire that followed.
  • When I reported this to Burwell by telephone, he called me a Chinese ace — in those days Chinese aces were pilots who cracked up their own airplanes […]
• 8

  To break.

  • We can send you a hundred pounds a month of pecans to crack up.

crack upadj/ˈkɹæk ˈʌp/

• 1

  Funny; hilarious

  • That joke was crack up.
  • "It was crack up!"