Peril means exposure to danger or the possibility of harm or loss. It can refer to a situation that is hazardous or potentially deadly, or to something that threatens someone's safety or well-being. Key senses:

• A noun: the state of being in danger (e.g., “They faced great peril during the storm.”).
• A thing that endangers (e.g., “The flood was a new peril to the town.”).
• In older or more formal usage, it can appear in phrases like “in peril” or “at your peril,” signaling someone risks harm by taking a certain action.

If you’d like, I can tailor the definition to a specific context (legal, literary, everyday usage) or provide example sentences.