mennäni
Mennäni is a Finnish word that translates to "my going" or "my departure." It is a nominalized form of the verb "mennä," which means "to go." The possessive suffix "-ni" indicates the first-person singular possessor. Therefore, "mennäni" specifically refers to the act of the speaker going somewhere or leaving.
The word can be used in various contexts. For example, in a sentence like "Mennäni oli äkillinen"
While "mennäni" is a grammatically correct construction, it is not exceptionally common in everyday spoken Finnish.