There are various synonyms to the term "straight-up-and-down," which refers to something that is vertical or perpendicular to the ground. Some of these words include "upright," "erect," "on end," "plumb," "perpendicular," "vertical," and "standing." These words are often used to describe structures, like a pole or a building, or objects, like a pencil or a ruler, that are positioned in a straight and upright manner. Additionally, "straight-up-and-down" can also be used figuratively to describe someone's honesty, integrity, and directness. In this context, synonyms may include "frank," "forthright," "candid," and "blunt".