| Singular | Plural | |
|---|---|---|
| Nominativ | dubium | dubia, dubiatis, haudubia |
| Genitiv | mandubii, dubi, dubiaeque, dubiose, dubiosus, dubitantus, dubii, dubitemne | dubiorum, mandubiorum |
| Dativ | dubio, dubioque | dubiisque, mandubiis, dubiis |
| Akkusativ | dubium | haudubia, dubia, dubiatis |
| Ablativ | dubio, dubioque | dubiisque, mandubiis, dubiis |
| Vokativ | dubium | dubia, dubiatis, haudubia |