| unColumnNo | Hedgehog.Internal.Source |
| unConfidence | Hedgehog.Internal.Property |
| unCoverCount | Hedgehog.Internal.Property |
| unCoverPercentage | Hedgehog.Internal.Property |
| uncurry | Hedgehog.Internal.Prelude |
| undefined | Hedgehog.Internal.Prelude |
| unEnvironment | Hedgehog.Internal.State |
| unfold | Hedgehog.Internal.Tree |
| unfoldForest | Hedgehog.Internal.Tree |
| unGenT | Hedgehog.Internal.Gen |
| unGroupName | Hedgehog.Internal.Property |
| unicode | Hedgehog.Internal.Gen, Hedgehog.Gen |
| unicodeAll | Hedgehog.Internal.Gen, Hedgehog.Gen |
| unLabelName | Hedgehog.Internal.Property |
| unLineNo | Hedgehog.Internal.Source |
| unlines | Hedgehog.Internal.Prelude |
| unOpaque | Hedgehog.Internal.Opaque, Hedgehog |
| unPropertyName | Hedgehog.Internal.Property |
| unPropertyT | Hedgehog.Internal.Property |
| unRec | Hedgehog.Internal.Barbie, Hedgehog |
| unRegion | Hedgehog.Internal.Region |
| unSize | Hedgehog.Internal.Range, Hedgehog.Range, Hedgehog |
| unTest | Hedgehog.Internal.Property |
| until | Hedgehog.Internal.Prelude |
| unwords | Hedgehog.Internal.Prelude |
| unzip | Hedgehog.Internal.Prelude |
| unzip3 | Hedgehog.Internal.Prelude |
| Update | Hedgehog.Internal.State, Hedgehog |
| updateNumCapabilities | Hedgehog.Internal.Queue |
| upper | Hedgehog.Internal.Gen, Hedgehog.Gen |
| upperBound | Hedgehog.Internal.Range, Hedgehog.Range |
| UseColor | Hedgehog.Internal.Config |
| userError | Hedgehog.Internal.Prelude |
| utf8 | Hedgehog.Internal.Gen, Hedgehog.Gen |