When someone is getting on your nerves, Italian has a specific set of expressions to tell them to stop: smetterla, finirla, and piantarla.
These are "pronominal verbs," meaning they have a pronoun permanently attached to them. In this case, the fixed pronoun la represents the annoying situation or behavior—the "it" in "stop it!"
Smetterla
Derived from smettere (to stop), smetterla means "to stop it." When giving a direct command to a single person (the tu form), use smettila. If you want to name exactly what they need to stop doing, follow it with the preposition con (with).
You can also leave the verb in its infinitive form when pairing it with a modal verb like dovere (to have to / must).
Finirla
Formed from finire (to finish), finirla translates to "to cut it out." Its tu command form is finiscila.
Piantarla
While piantare literally means "to plant" or "to abandon," the expression piantarla is a colorful, very common way to say "to knock it off." The command form is piantala.
Nuisance Behaviors
You will frequently use these verbs of cessation to put an end to behaviors that are fastidioso (annoying) or snervante (nerve-wracking). Two common verbs for describing this kind of nuisance are assillare (to pester) and stuzzicare (to tease).
