1. a white frost that forms on surfaces when water vapor in the air condenses directly into ice crystals

Examples

• The grass was covered with hoarfrost on the cold winter morning.
• Delicate hoarfrost decorated the bare tree branches like lace.
• The car windshield was thick with hoarfrost that had to be scraped off.
• Hoarfrost formed on the fence posts during the freezing night.
• The garden looked magical with hoarfrost sparkling in the early sunlight.
• We could see our breath in the air as we walked through the hoarfrost-covered field.