The antonym for "are on feet" would be "are off feet." This phrase signifies a situation where an individual is not standing, walking, or running but instead is resting or lying down. This may include resting on a couch, bed, or recliner or simply sitting on a chair. Being off your feet can provide a sense of relaxation and relief from the strain of daily activities. While being on your feet may indicate an active and productive lifestyle, being off your feet is essential for resting, rejuvenation, and recovery. Therefore, having a balance between these two states could be necessary for maintaining good health and wellbeing.