noun
A sport similar to tennis but played with softer rubber balls, popular in Japan and other Asian countries. Often simply called ソフトテニス in modern usage.
軟式庭球は、普通のテニスよりボールが柔らかい。
In soft tennis, the ball is softer than in regular tennis.
Compound of 軟式 (soft-style) and 庭球 (tennis, literally 'garden ball'). The term distinguishes the soft-ball variant from standard tennis.