| Under the Iron Sea | Under the Iron Sea |
| under the knife | bajo el cuchillo |
| Under the pretence of | Con el achaque de |
| Under the pretext of | So capa de |
| Under the Roofs of Paris | Bajo los techos de París |
| under way | en curso |
| under wraps | secreto |
| Under-mentioned | Más abajo |
| under-the-counter | bajo mano |
| under-the-table | bajo mano |
| underachieve | rendir menos de lo posible |
| underage | menor de edad |
| underarm | por debajo |
| underbrush | maleza |
| undercapitalization | financiación insuficiente |
| undercapitalize | proveer menos capital de lo necesario |
| undercarriage | armazón |
| undercharge | cobrar de menos |
| underclothes | ropa interior |
| underclothing | ropa interior |
| undercooked | crudo |
| undercover | secreto |
| undercover agent | agente secreto |
| undercurrent | corriente submarina |
| undercut | vender más barato |
| Underdark | Antípoda Oscura |
| underdeveloped | en vías de desarrollo |
| underdeveloped country | país subdesarrollado |
| underdog | seguro perdedor |
| underdone | poco hecho |
| underemployed | subempleado |
| underemployment | subempleo |
| underestimate | menospreciar |
| underexpose | subexponer |
| underfed | demacrado |
| underflow | agotamiento |
| underfoot | bajo los pies |
| undergarment | ropa interior |
| undergo | recibir |
| undergoes | vivido |
| undergone | vivido |
| Undergrads | Universitarios |
| undergraduate | estudiante |
| Undergraduate education | Pregrado |
| undergraduate student | estudiante no licenciado |
| underground | clandestino |
| Underground city | Ciudad subterránea |
| Underground culture | Cultura underground |
| underground level | sótano |
| underground railway | metro |
| underground train | metro |
| undergrowth | maleza |
| underhand | secreto |
| underhanded | secreto |
| underhandedly | clandestino |
| underhandedness | trapaceria |
| underlay | arpillera |
| underlie | estar debajo de |
| underline | acentuar |
| underling | subordinado |
| underlining | subrayado |
| underlying | subyacente |
| undermanned | falto de personal |
| undermentioned | abajo citado |
| Undermentionned | Más abajo |
| undermine | minar |
| underneath | abajo |
| Underneath Your Clothes | Underneath Your Clothes |
| Undernet | Undernet |
| undernourished | subalimentado |
| undernourishment | desnutrición |
| underpaid | mal pagado |
| underpants | bragas |
| underpass | paso subterráneo |
| underpay | pagar poco |
| underperform | menosdesempeñarse |
| underpin | apuntalar |
| underplay | restarse |
| underprivileged | desheredado |
| underrate | subestimar |
| underrated | subestimado |
| underscore | acentuar |
| undersecretary | subsecretario |
| undersell | malvender |
| undershirt | camiseta |
| underside | lado inferior |
| undersigned | infrascrito |
| undersize | demasiado pequeño |
| undersized | diminuto |
| underskirt | enaguas |
| understaffed | falto de personal |
| understand | pensar |
| understandable | comprensible |
| understanded | concepto |
| understanding | acuerdo |
| understate | atenuar |
| understatement | declaración incompleta |
| understeer | subviraje |
