The Third Infinitive Elative (-masta / -mästä)
In Finnish, verbs expressing stopping, forbidding, or preventing require the action being stopped to be in the third infinitive elative form. You can think of this form as meaning "from doing" an action.
- Form it by adding -masta or -mästä to the verb's strong stem (the same stem used for the he form).
- For example: kiroilla (to swear) becomes kiroilemasta, and lyödä (to hit) becomes lyömästä.
Stopping an Action with "Lakata"
The verb lakata means "to stop" or "cease" an ongoing action. Because you are conceptually moving away from the activity, the activity takes the -masta / -mästä ending.
| He did not stop swearing, so I had to leave. | Hän ei lakannut kiroilemasta, joten minun täytyi lähteä. |
| Stop fighting and clean the room! | Lakatkaa tappelemasta ja siivotkaa huone! |
Forbidding with "Kieltää"
When you use kieltää (to forbid), you forbid someone from doing something. The person being forbidden acts as the object and takes the partitive case (e.g., opiskelijoita, poikaa), while the action verb takes the -masta / -mästä ending.
| The teacher forbade the students from swearing in the classroom. | Opettaja kielsi opiskelijoita kiroilemasta luokassa. |
| The mother forbade the boy from hitting the dog. | Äiti kielsi poikaa lyömästä koiraa. |
Preventing with "Estää"
Similarly, estää means "to prevent" or "stop someone from" doing something. It works exactly like kieltää: the target being stopped takes the partitive case, and the prevented action takes the -masta / -mästä ending.
| We are trying to prevent him from hitting others. | Me yritämme estää häntä lyömästä muita. |
| You must prevent the dog from chewing the shoe. | Sinun on estettävä koiraa pureskelemasta kenkää. |
Everyday Rules and Habits
These structures are especially common when dealing with bad habits, enforcing rules, and preventing accidents.
| If the dog does not stop barking, the neighbor will get angry. | Jos koira ei lakkaa haukkumasta, naapuri suuttuu. |
| I must watch the child and prevent him from falling. | Minun täytyy vahtia lasta ja estää häntä putoamasta. |
