From Longman Dictionary of Contemporary Englishno laughing matterno laughing matterinformalSERIOUS/NOT JOKING something serious that should not be joked about It’s no laughing matter having to walk by a group of rowdy drunks every night just to get home. → laugh
Examples from the Corpus
no laughing matter• Dole and his staff know that age discrimination is no laughing matter.• But Dole and his staff know the age issue is no laughing matter.• But it is no laughing matter.• But the issue of physicians and their handwriting is no laughing matter.• I am a gout sufferer, and it's no laughing matter.• The second Fleet Street sensation was no laughing matter.• They looked as though they knew already that life was no laughing matter.• This Jell-O-head business is no laughing matter.• It is no laughing matter, however. 