The phrase "checking on" is commonly used to indicate an action of reviewing or verifying a situation or person. However, there are plenty of synonyms that can be used to depict the same kind of action. Some such words include 'investigating,' 'inspecting,' 'questioning,' 'inquiring,' 'monitoring,' 'examining,' 'verifying,' and 'scrutinizing.' While each of these words carries a slightly different connotation, they all imply a form of investigation or assessment. Depending on the context, a synonym for "checking on" can be used to add variety and precision to written or spoken communication.