Noun
(sports) A certain wrestling move that traps the opponent's leg.
Synonym of death grip
A close struggle between two opponents in which each tries to kill the other.
(metaphoric) A struggle to destroy a force or principle to which one is opposed, or between two mutually incompatible principles.
Rigor mortis, or a physical grip that is similarly inflexible and unyielding.
(metaphoric) A similarly tight hold on something nonphysical.
Source: en.wiktionary.org