This is the 5937th most frequent Japanese word.
やわ
"やわ" can mean "soft" or "gentle" in casual or colloquial contexts.
In this case, "やわらかい" refers to the attribute of the towel being soft.
このタオルはやわらかい。
This towel is soft.
Here, "やわらかい" is used metaphorically to describe someone's heart as gentle or kind.
彼の心はとてもやわらかい。
His heart is very gentle.
The usage "やわやわ" emphasizes a soft and delicate texture.