Indemnifier /ɪnˈdɛmnɪfʌə/ (n.)
1. Damocles; an indemnitor (archaic). One who, out of a surfeit of incaution or deal fatigue, has underwritten every minor calamity her counterparty may suffer; every debatable opportunity it may forgo, and every extraordinary expense it may incur, however irrational, in the performance of the contract between them.
2. (Unusual) One who, in full knowledge of the facts, has agreed to be responsible for a well-quantified and clearly-articulated externality that its counterparty may suffer while providing an incontrovertible benefit to the indemnifying party through no fault of its own.