1. Of sound waves with frequency greater than 1000 million hertz 
2. Moving at more than five times the speed of sound

Encyclopedia: Hypersonic

• unverbalised
• unverbalized
• unverifiable
• unverified
• unversed
• unvigilant
• unvindictive
• unvitrified
• unvoiced
• unvoluntary
• unvulcanised
• unvulcanized
• unwanted
• unwantedly
• unwarily
• unwariness
• unwarmed
• unwarrantable
• unwarrantably
• unwarranted
• unwary
• unwashed
• unwatchful
• unwavering
• unwaveringly