"Cross one's eyes" is an idiomatic expression used to describe a person's act of intentionally turning their eyes inward and making them appear cross-eyed. It is often associated with silly and comical situations. Some common synonyms for this expression include "squint," "strabismus," "esotropia," "lazy eye," and "wall-eyed." These terms are often used in medical contexts to describe eye abnormalities and disorders. However, when used colloquially, they can also refer to the act of purposely making one's eyes look strange or humorous. Whatever the context, these synonyms can add some variety and color to one's vocabulary.