-iv
Nouns ending in -iv are almost always das.
German does not build these — the words arrived whole.The words came from Latin.
Examples
- das Motiv
- das Archiv
- das Adjektiv
- das Objektiv
- das Passiv
Plural
- das Motiv → die Motive
One exception
A person is der: der Detektiv.
- der Detektiv