Infinitive Simple Past Past Participle
| unbend | unbent | unbent |
| unbind | unbound | unbound |
| unclothe | unclothed / unclad | unclothed / unclad |
| underbid | underbid | underbid |
| undercut | undercut | undercut |
| underfeed | underfed | underfed |
| undergo | underwent | undergone |
| underlie | underlay | underlain |
| undersell | undersold | undersold |
| underspend | underspent | underspent |
| understand | understood | understood |
| undertake | undertook | undertaken |
| underwrite | underwrote | underwritten |
| undo | undid | undone |
| unfreeze | unfroze | unfrozen |
| unhang | unhung | unhung |
| unhide | unhid | unhidden |
| unknit | unknitted / unknit | unknitted / unknit |
| unlearn | unlearned / unlearnt | unlearned / unlearnt |
| unsew | unsewed | unsewn / unsewed |
| unsling | unslung | unslung |
| unspin | unspun | unspun |
| unstick | unstuck | unstuck |
| unstring | unstrung | unstrung |
| unweave | unwove / unweaved | unwoven / unweaved |
| unwind | unwound | unwound |
| uphold | upheld | upheld |
| upset | upset | upset |