| Singular Nominative | fionnachtain |
| Singular Genitive | fionnachtana |
| Plural Nominative | fionnachtana |
| Plural Genitive | fionnachtana |
| Singular Nominative | an fhionnachtain |
| Singular Genitive | na fionnachtana |
| Plural Nominative | na fionnachtana |
| Plural Genitive | na bhfionnachtana |