What is need to completely describe speed?

To completely describe speed, one must specify both the magnitude and the direction of movement. Speed is a scalar quantity, which means it only requires a numerical value (e.g., 60 km/h) to indicate how fast an object is moving. However, when discussing motion in a more comprehensive sense, velocity is used, which incorporates both speed and direction (e.g., 60 km/h north). Therefore, while speed can be described with magnitude alone, a complete description of motion involves the inclusion of directional information.