- undamaged
- unsoiled
- unspotted
- untainted
- untarnished
- unsociable
- unsociableness
- unsociability
- unearned
- unstratified
- unlawful carnal knowledge
- urogenital system
- urogenital apparatus
- unchangeability
- unchangingness
- unchangeableness
- unthematic
- unconverted
- unethically
- untier
- unfastener
- unmanageable paraphernalia
- unexploited
- unitised
- uniocular diplopia
- uniocular polyopia
- unconstitutionality
- unrefreshed
- unsex
- used only as the second member in the compound
- unnaturally
- under roof
- unfailingly
- urinalysis
- uranalysis
- unnumberable
- unnumerable
- unmistakably
- unmistakeably
- unintelligibly
- unclearly
- unfocusedly
- undergrazing
- unclearness
- uncloudedness
- unallowable digit
- unmalleability
- unpleasant utterance
- unrevealing
- unenviable