all one's strength; desperate effort
Almost always used in the set phrase 死力を尽くす, meaning to exert every ounce of strength as if one's life depended on it. The literal sense 'strength when ready to die' is rarely used outside this expression.
See also: 死力を尽くす
He exerted all his strength to solve the problem.
The players fought with desperate effort.
Compound of 死 (death) and 力 (strength), literally 'death-strength'. The exact historical derivation is uncertain, but the meaning is conventionally associated with the idea of strength summoned in a life-threatening situation.