essivi

Essive, known in Finnish as essiivi, is a grammatical case used in some Finnic languages to express a temporary state or role, roughly translating to "as a" in English. It is most clearly described in Finnish and Estonian linguistic descriptions, and it is part of the set of cases that mark spatial or functional relationships separate from the nominative, genitive, or other cases.

In Finnish, the essive is formed by adding the suffix -na or -nä to the noun stem, with vowel harmony affecting the form. For example, oppettaja becomes opettajana meaning "as a teacher," and opiskelija becomes opiskelijana meaning "as a student." The essive signals how something is being regarded during a period or in a specific capacity, such as "flight attendants as crew" or "he spoke as a witness." It is typically distinct from the translative case, which marks a change of state or becoming (often using -ksi), and from the inessive case, which denotes being inside or in a state of existence.

In Estonian, the essive serves a similar function, with phrases like Ta on õpetajana meaning "He is a teacher" or "as a teacher." The case is used for temporary roles and states, and it interacts with the language’s broader system of cases that mark means, manner, or perspective. In both languages, the essive is more common in written or formal registers and can appear in set phrases or literary contexts, whereas everyday speech often relies on alternative constructions.

Overall, the essive provides a way to describe temporary identity, function, or state, marking how something is viewed during a particular time or circumstance.