noun, noun which may take the genitive case particle 'no'
softness; flexibility; elasticity
Used as a noun or adjectivally with の to describe materials, substances, or abstract qualities that are soft, pliable, or flexible. Often contrasts with 硬性 (こうせい, hardness).
この素材は軟性が高く、加工しやすい。
This material has high flexibility and is easy to process.
軟性のプラスチックは衝撃に強い。
Soft plastics are resistant to impact.