When it comes to describing someone who is standing upright, the phrase "stood erect" might come to mind. However, there are many other synonyms that can be used to add variety and descriptive nuance to your writing. Some possible alternatives include "stood tall," "stood straight," "stood upright," "stood firm," "stood resolutely," "stood unbent," "stood unyielding," "stood at attention," and "stood poised." By experimenting with different synonyms, you can bring more vividness and depth to your descriptions, allowing readers to better visualize the actions and emotions of your characters.