2) Usually with a possessive suffix (active only). 3) Some uses of the verbal noun are called the 'fourth infinitive' by certain sources (more details). 4) Usually with a possessive suffix. May not be used with all verbs, especially intransitive ones (more details). Distinct from nouns with the -ma suffix and third infinitive forms.
* The third-person singular indicative form vuorovaikuttaa does not exhibit final gemination, unlike the first infinitive (the lemma form), even though they are spelled identically.
