"Trackless waste" can be replaced with various synonyms to convey the same meaning. Some options include "desolate wilderness," "barren wasteland," "unfathomable void," "vast emptiness," and "unforgiving terrain." Each of these phrases paints a vivid picture of a desolate area devoid of any signs of life or civilization. They can be used to describe uninhabited areas such as deserts, tundras, and deep wilderness. The use of these synonyms can add depth and detail to a description, allowing readers to visualize and better understand the environment being discussed. Ultimately, the choice of which synonym to use will depend on the context and tone of the writing.