smart casual
US /ˌsmɑːrt ˈkæʒ.u.əl/
UK /ˌsmɑːrt ˈkæʒ.u.əl/

1.
elegante casual, casual de negocios
a dress code that is neat, conventional, and relatively informal, typically for a workplace or social event
:
•
The invitation specified smart casual attire.
La invitación especificaba vestimenta elegante casual.
•
For the office party, the dress code is smart casual.
Para la fiesta de la oficina, el código de vestimenta es elegante casual.