tone up
verb
High School
1
To cause to give a higher tone or sound; to give a higher tone to; to make more intense; to heighten; to strengthen.
2
To firm and strengthen the muscles of the body by regular exercise.
To cause to give a higher tone or sound; to give a higher tone to; to make more intense; to heighten; to strengthen.
To firm and strengthen the muscles of the body by regular exercise.