- Unity
- Unity is strength
- Universal
- Universal conquest
- Unluckiness
- Universal gravitation
- Universality
- Universe
- Unjust
- Unjustified
- Unknown
- Unladen
- Unlawful
- Unleaded
- Unlearned
- Unlearnt
- Unleavened
- Unlicensed
- Unlikely
- Unlined
- Unload
- Unlock
- Unlooked-for
- Unlovely
- Unmanageable
- Unmanned
- Unmannerly
- Unmentionables
- Unmindful
- Unmistakable
- Unnatural
- Unnatural death
- Unnaturally
- Unnerving
- Unobservant
- Unobtrusive
- Unpack
- Unplanned
- Unpleasantness
- Unpolished
- Unprepossessing
- Unprintable
- Unproblematic
- Unpromising
- Unprompted
- Unproven
- Unprovoked
- Unpublished
- Unquenchable
- Unquestioning
- Unquote
- Unreadable
- Unrefined
- Unreliable
- Unremarked
- Unrepresentative
- Unreservedly
- Unresponsive
- Unrest
- Unrestrained
- Unripe fruit
- Unroll
- Unsafe
- Unsaid
- Unsanctioned
- Unsaturated
- Unscrew
- Unseasoned
- Unshakable
- Unshared
- Unsheathe
- Unsheltered
- Unshielded
- Unshod
- Unskillful person
- Unsolicited
- Unspeakable
- Unspecified
- Unstated
- Unsteady man
- Unstinted
- Unstintingly
- Unsuitable
- Unsuitably
- Unsuited
- Unsullied
- Unsure
- Unsusceptible
- Unsustainable
- Unsystematically
- Untasted
- Unthought of
- Untidiness
- Until death
- Untiring
- Untowardness
- Unutterable
- Unvarnished
- Unvarying
- Unversality