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1879, Latin, literally "way of living or getting along" (see modus).
Modus vivendi is any temporary compromise that enables parties to carry on pending settlement of a dispute that would otherwise paralyse their activities. [Fowler]
A compromise between adversaries that allows them to get along temporarily: “During the separation, my parents adopted a modus vivendi that enabled them to tolerate each other.” From Latin, meaning a “method of living.”