A vector has a specific direction as well as a size, with a unit: pressure, electrical current and even the flow of heat are all vectors. A vector quantity has both magnitude and direction.
Force, velocity, weight, and acceleration are examples of vector quantities.
A scalar quantity has size only, with a unit. There are many more scalar quantities: temperature, work, power and electrical resistance are all scalars. A scalar quantity has only magnitude.
Speed, density, energy, and mass are examples of a scalar quantity.