- umbelliform
- unembarrassed
- unquestionableness
- unheeding
- unservile
- unsubmissive
- urologist
- unbraided
- unhurriedness
- uneven ventilation
- unstready
- unskilled person
- unhistorical
- unquietly
- unconscious process
- unknowability
- unobstructedly
- unsworn
- unobserved
- unconstitutional
- underground water
- unmodified instruction
- used in compound words—meaning man
- united nations university
- unemployment compensation
- unnoticeable
- unobservable
- underpay
- uncurving
- undercover operation
- under the counter
- unmitigated
- unlatched
- unbolted
- unworthily
- unqualifiedly
- unplucked
- unchangeably
- unwedded
- unconfirmed report
- upright piano
- unsubstantiated
- unproven
- unwholesome tendency
- uranology
- unobtrusiveness
- uvulae
- uranography
- uveal ectropion
- unperceived