| Singular | Plural | |
|---|---|---|
| Nominativ | efficax | efficaces, efficacia |
| Genitiv | efficacis | efficacium |
| Dativ | efficaci | efficacibus |
| Akkusativ | efficacem, efficax | efficacis, efficaces, efficacia |
| Ablativ | efficaci | efficacibus |
| Vokativ | efficax | efficaces, efficacia |
| Singular | Plural | |
|---|---|---|
| Nominativ | efficacior, efficacius | — |
| Genitiv | — | — |
| Dativ | — | — |
| Akkusativ | efficacius | — |
| Ablativ | efficaciore | — |
| Vokativ | efficacior, efficacius | — |
| Singular | Plural | |
|---|---|---|
| Nominativ | efficacissimum, efficacissima, efficacissimus | efficacissima, efficacissimae |
| Genitiv | efficacissimae | — |
| Dativ | efficacissimae | efficacissimis |
| Akkusativ | efficacissimum, efficacissimum, efficacissimam | efficacissimas, efficacissima |
| Ablativ | efficacissima | efficacissimis |
| Vokativ | efficacissime, efficacissimum, efficacissima | efficacissima, efficacissimae |