Definition of do-or-die
- a do-or-die situation
adamant, adamantine, dogged, hard, hardened, hardheaded, headstrong, immovable, implacable, inflexible, mulish, obdurate, persistent, pertinacious, perverse, pigheaded, rigid, self-willed, stubborn, tenacious, unbending, uncompromising, unrelenting, unyielding, willful (or wilful);
on one's mettle;
: very determined
—used to describe a situation in which you have to do something or you will fail, lose, etc.
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