1. Describing the purchase of a property (usually real estate) before it is constructed or completed, based on architectural plans and drawings rather than the finished product
They decided to buy the apartment off plan to get a better price.
Eles decidiram comprar o apartamento na planta para obter um preço melhor.
2. Not according to a predetermined plan or schedule; improvised or unplanned
The project went off plan when unexpected issues arose.
O projeto saiu do plano quando surgiram problemas inesperados.