Definition of split one's sides in US English:

split one's sides

(North American split a gut)

phrase

informal
  • Be convulsed with laughter.

    ‘the dynamic comedy duo will have you splitting your sides with laughter’
    • ‘They will be splitting their sides in London over the spectacle of yet another Scottish solution to a Scottish problem.’
    • ‘Everyone split their sides, they were laughing so hard.’
    • ‘No second-rate seat would have withstood the pressure from two young children bouncing up and down with glee for two hours, splitting their sides and shouting themselves hoarse.’
    • ‘The so-called class enemies of capitalists must be splitting their sides.’
    • ‘They can bring tears or make people split their sides with laughter.’
    • ‘I bought the book for my husband - we're both avid campers - and I've nearly split my sides laughing at the encounters with rattlesnakes and bears.’
    • ‘We want people to come, split their sides laughing and then go home in great form.’
    • ‘This year they will have audiences splitting their sides with laughter with their crazy antics.’
    • ‘As his costume split its seams, audiences split their sides.’
    • ‘To tell you the truth, we got as much fun from that incident as we did from winning the final, and I'd say whenever we met thereafter rarely an occasion passed when we didn't split our sides.’
    roar with laughter, laugh, guffaw, roar, laugh loudly, howl with laughter, dissolve into laughter, be creased up, be doubled up
    View synonyms