This is the 2390th most frequent Japanese word.
ソフトテニス
Soft tennis: A variation of tennis played with softer balls, lighter rackets, and on smaller courts.
In this sentence, 'ソフトテニス' is a noun that refers to the sport of Soft Tennis. It is the object of the verb '好き' (like).
私はソフトテニスが好きです。
I like Soft Tennis.
Here, 'ソフトテニス' is the subject of the sentence. It is described as being lighter, in comparison to regular tennis.
ソフトテニスは普通のテニスよりも軽いです。
Soft Tennis is lighter than regular tennis.
'ソフトテニス' acts as the object of the action 'する' (to do/play). It specifies the activity being performed in the school context.