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Adjective: rib-tickling  'rib,ti-k(u-)ling
Usage: informal
  1. Arousing or provoking laughter
    "The comedian's rib-tickling jokes had the audience in stitches";
    - amusing, comic, comical, funny, laughable, mirthful, risible

See also: humorous, humourous [Brit, Cdn, non-standard]