knag /nag/

1. A knot in wood
2. A peg

knaggˈiness noun

• ultrasound
• ultrasounds
• ultrastructure
• ultrastructures
• ultra-tropical
• ultraviolet
• ultraviolet microscope
• ultraviolet spectroscopies
• ultraviolet spectroscopy
• ultraviolet star
• ultraviolet stars
• ultra vires
• ultra-virtuous
• ultroneous
• ultroneously
• ultroneousness
• ultroneousnesses
• ululant
• ululate
• ululated
• ululates
• ululating
• ululation
• ululations
• ulva