b.(to resist, etc.) to the last extremity: to the death. †to expect the extremity: to be prepared for the worst or for death.
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1684 London Gaz. No. 1969/2 The Besieged..seem resolved to expect the Extremity.
1856 R. W. EmersonEng. Traits xi. 182 Mirabeau wrote prophetically from England, in 1784, ‘..The English tenant would defend his lord to the last extremity.’