mauvais quart d'heure - Wiktionary, the free dictionary

Unadapted borrowing from French mauvais quart d’heure (“bad quarter of an hour”).

• IPA^(key): /məʊˌveɪ kɑː(ɹ) ˈdɜː(ɹ)/

mauvais quart d'heure (plural mauvais quarts d'heure)

1. (chiefly British) A brief unpleasant period.
   • 1898 April 13, Henry Adams, “[Letter]”, in Ernest Samuels, editor, Henry Adams: Selected Letters, published 1992, →ISBN, page 343:

     It was a mauvais quart d’heure, the Christmas holidays of ’96, and poor Willy Phillips never lived to see the fight recovered.

• “mauvais quart d’heure, n.”, in OED Online  ⁠, Oxford, Oxfordshire: Oxford University Press, launched 2000.