1. to be inappropriate, unsuitable, or not conforming to accepted standards of behavior or propriety
It would be improper to arrive late to a formal dinner without notification.
Seria impróprio chegar atrasado a um jantar formal sem aviso prévio.
2. to be incorrect or inaccurate in a technical or formal context
The use of colloquial language would be improper in an academic essay.
O uso de linguagem coloquial seria impróprio em um ensaio acadêmico.
3. to violate social conventions or etiquette
It would be improper to discuss personal finances at a business meeting.
Seria impróprio discutir finanças pessoais em uma reunião de negócios.