Final answer:
The antonym for harshness is gentleness, indicating a mild and tender approach as opposed to the severity represented by harshness.
Step-by-step explanation:
The antonym for harshness is gentleness. Harshness refers to a quality of being stern or severe, not only in sound but also in behavior or conditions. In contrast, gentleness suggests a mild, kind, or tender temperament or approach, often exemplified by a soft touch or a soothing voice.
To understand further, where harshness might describe the abrasive tone of a voice or the rough handling of an object, gentleness would be the opposite, showcasing calmness and a light, careful touch.