crack up

present singular third person cracks up · participle present cracking up · participle past cracked up · past cracked up

1. To laugh.
   1. idiomaticintransitiveTo laugh heartily.

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

   2. idiomatictransitiveTo cause to laugh heartily.

      The joke about the nuns in the bath cracked me up.

      1 more example

      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.

      2022 October 21, Jason Bailey, “How George Clooney and Julia Roberts Quietly Became the Tracy-Hepburn of Our Time”, in The New York Times

   3. intransitiveslangTo tease (someone) or tell jokes at the expense of (someone).

      He's always cracking up at me about that.

2. To break.
   1. datedidiomaticintransitiveTo become insane; to suffer a mental breakdown.

      She got through the war, but cracked up when her sister died.

      1 more example

      All rather inhuman and undernourished, isn’t it? Well, that, children, is the true sign of cracking up.

      1936 February, F. Scott Fitzgerald, “The Crack-Up”, in Esquire

   2. idiomaticTo break down or fall apart; to stop functioning; to shatter.

      My motorcycle cracked up before I arrived.

      1 more example

      The university was really cracking up, losing faculty, students and donors, and it seemed like to go under.

   3. idiomatictransitiveTo separate a group.

      I have to crack up that little clique.

   4. USTo crash an aircraft or automobile.

      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 […]

      1983, John Thorn, David Reuther, The Armchair Aviator, page 101

      1 more example

      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.

      1930 December, Lawrence M. Guyer, “Chuck Luck: The Story of a Flying Dog”, in Boys' Life

   5. transitiveTo remove the shell from nuts.

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

   6. transitiveTo crack (petroleum). (to break down (a complex molecule), especially with the application of heat: to pyrolyse)

      The refinery cracks up the heavier oils.

3. To affect the image of something.
   1. slangtransitiveTo praise or applaud (something); to promote a positive view of (something).

      She wasn't as impressive as Katie cracked her up.

   2. datedtransitiveTo insult, demean or harm the image of (something).

      Those who have been cracking up the agricultural industry will hopefully reconsider their denigration of it.

   3. informaltransitiveusually passive voiceTo cry up; to extol.

      This new computer system is not what it was cracked up to be.

      1 more example

      No use, with a bloke like this, cracking up your own merits. Stick to the truth.

      1939 June, George Orwell [pseudonym; Eric Arthur Blair], chapter IX, in Coming Up for Air, London: Martin Secker & Warburg, published 1948 (April 1959 printing), →OCLC, part II, page 132

4. intransitiveslangTo smoke crack cocaine.

   I need to crack up.

comparative more crack up · superlative most crack up

1. New ZealandcolloquialFunny; hilarious

   That joke was crack up.

   3 more examples

   "It was crack up!"

   2017 April 23, “McDonald's say 'neigh' to horses through the drive-thru”, in Stuff

   In town people would stop and say to me, “Hey Becky, that cat story was crack up.”

   2020 April 20, “The curious case of a fictional spa in Westport”, in Newsroom

   One person said it was "crack up", while the woman who uploaded it said "I'm a do it again (sic)".

   2020 June 5, “Police looking into footage of woman twerking on Auckland Harbour Bridge”, in Newshub, archived from the original on 20 Sep 2020