KEY: Orifice.
SYN: Aperture, perforation, mouth, opening, hole, bung, bunghole.
ANT: Obstruction, stopper, plug, imperforation.

• Ungainly
• Ungovernable
• Ungraceful
• Ungrateful
• Ungulp, [See GULP]
• Unhandy
• unhappiness
• Unhappy
• Unhealthy, [See BEHALF]
• Uniform
• Uninteresting
• Uninterrupted
• Union
• Unique
• Unison
• Unit
• Unite
• Unity
• Universal
• Unjust, [See COMMON]
• Unknown
• Unlawful, [See OBSCURE]
• Unlearned, [See EAST]
• Unlike, [See LEARNED]
• Unlimited, [See_PURE]