sine die UK /ˈsʌɪ.ni ˈdaɪ.iː/US /ˈsaɪ.ni ˈdaɪ.i/ adverb1 •Without specifying a date (for a future event); indefinitely.Years ago […] he might have retrieved his position; but he had done what most people will do in such cases—put off the evil day sine die, and gone on increasing his enormous list of debts. — 1860