Rotundly is a word that describes something that is round, plump, or chubby. Some synonyms that can be used in its place include plumply, corpulent, portly, chubby, and roundly. All of these words convey a sense of roundness or fullness, but they can each have slightly different connotations. "Corpulent" may imply a greater degree of excess weight than some of the other terms, while "roundly" can also refer to a shape that is circular in nature without necessarily being chubby or overweight. Other synonyms for rotundly include "fleshy", "pudgy", "full-bodied", "thickset", and "barrel-chested". These words can be useful for adding variety to your writing or to better convey the meaning you intend to express.