Wiktionary
underexercise
n. Insufficient exercise. vb. (context intransitive English) To take too little exercise.
Usage examples of "underexercise".
Already I know Carrie is malnourished, underexercised and underdeveloped for her age.
Most pets are overfed and underexercised, much too pampered and often bored.
Overfed and underexercised, they did not even run like normal children.
I give lectures on the perils of overeating and underexercise, and no one listens to those.