1. the soft, fine wool that grows close to the skin of sheep and other wool-bearing animals, beneath the coarser outer wool

Examples

• The underwool provides excellent insulation for the sheep during winter.
• Cashmere is made from the soft underwool of goats.
• Shearers separate the coarse outer wool from the valuable underwool.
• The underwool is much finer and softer than the guard hairs.
• Premium wool products often use only the underwool for their softness.
• The animal’s underwool helps regulate body temperature in harsh climates.