1. Having no ribs or no visible ribs

Antonym: ribbed

• unveiled
• unveiling
• unvendible
• unvented
• unventilated
• unverbalised
• unverbalized
• unverifiable
• unverified
• unversed
• unvigilant
• unvindictive
• unvitrified
• unvoiced
• unvoluntary
• unvulcanised
• unvulcanized
• unwanted
• unwantedly
• unwarily
• unwariness
• unwarmed
• unwarrantable
• unwarrantably
• unwarranted