lit. a needle concealed in silk floss (idiom); fig. ruthless character behind a gentle appearance; an iron fist in a velvet glove; a wolf in sheep's clothing
柔软的东西里面藏着针。比喻外表看来和善，内心却很尖刻。也比喻柔中有刚。
偏正式；作谓语、定语、状语；
绵：丝棉。棉絮里面藏着针。形容柔中有刚。也比喻外貌和善，内心刻毒。
元·石君宝《曲江柳》第二折：“笑里刀剐皮割肉，绵里针剔髓挑筋。”