| One-time code | One-time password |
| One-time-pad | One-time pad |
| One-Two-GO | One-Two-GO Airlines |
| onecht | false |
| onecht kind | bastard |
| onechte breuk | improper fraction |
| Onechte gaviaal | False gharial |
| Onechte karetschildpad | Loggerhead Sea Turtle |
| Onechte koraalslang | Anilius scytale |
| Onechte spitskopschildpad | Western Swamp Tortoise |
| Onechte waterrat | False Water Rat |
| oneconomisch | uneconomical |
| oneer | discredit |
| oneerbaar voorstel | improper suggestion |
| oneerbiedig | ill-mannered |
| oneerbiedigheid | disrespect |
| oneerlijk | unfair |
| oneerlijk verkregen | ill-gotten |
| oneerlijkheid | deceitfulness |
| oneetbaar | inedible |
| oneffen | uneven |
| oneffen maken | coarsen |
| Onega | Onega |
| Onegameer | Lake Onega |
| oneigenlijk | figurative |
| oneigenlijke breuk | improper fraction |
| oneindig | deeply |
| oneindig klein | infinitesimal |
| oneindige | infinity |
| oneindigheid | infinity |
| Oneiroi | Oneiroi |
| onelastisch | inelastic |
| onelegant | awkward |
| Oneliner | One-liner joke |
| Onemanshow | One person show |
| onenigheid | difference |
| onenigheid brengend | divisive |
| OneRepublic | OneRepublic |
| onervaren | green |
| onervarenheid | inexperience |
| Onesimus | Onesimus |
| oneven | odd |
| onevenredig | disproportionate |
| onevenredigheid | disproportion |
| onevenwichtig | unstable |
| onevenwichtigheid | imbalance |
| Oneworld | Oneworld |
| Oneşti | Oneşti |
| onfalsifieerbaarheid | unfalsifiability |
| onfatsoenlijk | indecent |
| onfatsoenlijk voorstel | improper suggestion |
| onfatsoenlijkheid | misconduct |
| onfeilbaar | foolproof |
| onfeilbaarheid | infallibility |
| onfortuinlijk | abortive |
| Ong Khan | Wang Khan |
| ongastvrij | inhospitable |
| ongastvrijheid | inhospitality |
| ongeacht | despite |
| ongearticuleerd | indistinctly |
| ongebluste kalk | quicklime |
| ongebonden | footloose |
| ongebondenheid | licentiousness |
| ongeboren | unborn |
| ongebreideld | immoderate |
| ongebruikelijk | unusual |
| ongebruikt | idle |
| Ongebukt | Law |
| ongecensureerd | uncut |
| ongecompliceerd | simple |
| ongecompliceerdheid | simplicity |
| ongecontroleerd | uncontrolled |
| ongedaan maken | annul |
| ongedeeld | undivided |
| ongedeerd | safe |
| ongedekt | uncovered |
| ongedekt zijn | bounce |
| ongedesemd | unleavened |
| ongedesemde | unleavened |
| ongedierte | pest |
| ongediertebestrijding | pest control |
| ongedifferentieerd | indiscriminate |
| ongedisciplineerdheid | indiscipline |
| ongeduld | impatience |
| ongeduldig | restive |
| ongedurig | restless |
| ongedwongen | casual |
