Learn Finnish: Mikä tapaus tämä on? Katoamista ei kuvailtu hyvin. - What case is this? The disappearance was not described well.

To say something 'was not done', you use the negative word ei plus the passive past participle. For the verb kuvailla (to describe), the positive past passive is kuvailtiin (was described). By dropping the -in at the end, you get the passive participle kuvailtu. Together, ei kuvailtu means 'was not described'.

Why is katoamista in the partitive case?

In Finnish, the object of a negative sentence must always be in the partitive case. In a passive sentence, the thing receiving the action (the disappearance) is grammatically the object. Because it was not described, the basic form katoaminen changes to the partitive katoamista.

Where does the word katoamista come from?

It comes from the verb kadota (to disappear). By adding the -minen ending to the verb stem, it becomes the noun katoaminen (disappearance). Words ending in -minen are very common in Finnish and behave predictably: their partitive always ends in -mista.

Can I use tapaus to ask about grammar cases, like 'What case is the partitive?'?