Negative: nu pleca, nu plecați

To tell someone not to do something, the two forms of address work differently.

• Tu: nu + the infinitive without a. a pleca → nu pleca, a uita → nu uita, a face → nu face, a fi → nu fi.
• Voi and polite: nu + the usual plural form. nu plecați, nu uitați, nu faceți, nu fiți.

So you say Radu, nu pleca! (Radu, don't leave!), never nu pleacă, which means "he doesn't leave". Irregular affirmative forms disappear in the tu negative: vino becomes nu veni, fii becomes nu fi.

Copii, nu alergați! (Children, don't run!) · Domnule, nu fumați aici! (Sir, don't smoke here!)