| Abbreviation | Definition |
|---|---|
| UI | yoU and I |
| UI | yoU Idiot |
| UIC | Unit Identification Code |
| UIL | Using I Loosely |
| UIP | Use In Place |
| UIVMM | Unless I'm Very Much Mistaken |
| UJK | You Joking |
| UK | U Know |
| UK | Usher's Keep |
| UKR | Ur Kidding Right? |
| UKW | You Know What |
| UKWIM | You Know What I Mean |
| UL | UnLucky |
| UL | Utterly Lazy |
| ULD | U Little Dummy |
| ULL | You Little Liar |
| ULM | You Love me |
| ULT | Uh Like That |
| UM | Up Mine |
| UMF | Ultimate Mind F*** |