If you realize mid-climb that your rock climbing rope is frayed, you might be in peril. The word peril means imminent danger to life and limb.
Peril comes from the Latin peric(u)lum, meaning danger. Today it's often used in tandem with the word mortal, which relates to death. For example, you're in mortal peril when you're flying down a cliff-side trail on your mountain bike and you hit loose gravel. Peril can also describe dangers of a less physical sort, though it's less common. If your employer sinks your 401K into what turns out to be a Ponzi scheme, he's put your retirement in peril.