periculum

Periculum, periculi, n., second declension. The root is the one behind experior, "try out", so the oldest sense is "a trial, a test" and "danger" is what a test turns into when it can go badly. That older meaning survives in periclitor, "to make trial of", and in the legal periculum, the risk a party carries.

Watch the case. Danger to someone is periculum with the dative or with a genitive of the thing feared: periculum mortis is the danger of dying, not a danger belonging to death. In periculo esse is the standard "to be in danger", and periculum facere alicuius rei is "to make trial of something". English peril, perilous and imperil all come straight through French, and experiment sits on the same root at one remove.