the world > health and disease > ill health > a disease > disorders of visible parts > skin disorders > afflict with or cause a skin disorder [verb (transitive)] > render hard (2)
transitive. To harden; to render callous; also figurative. Obsolete (at least in figurative sense).
transitive. To cause (a part of the body, esp. the hands or feet) to develop calluses, typically through strenuous or repetitive work or activity.