contemptible, contemptuous

Contemptible or contemptible describes something low or disgraceful; deserving scorn or disdain ( contempt ) --
He showed a complete lack of concern; it was contemptible.
His attitude is contemptible; if I were his boss I'd fire him.

Contemptuous or contemptuous means showing or expressing scorn or disdain ( contempt ) --
The public admired the new statue, but the critics were contemptuous.
He doesn't actually comment on any topic; he is merely contemptuous of the opinions of others.

Now that you know that, you can say --
"Of course she was contemptuous; his behavior was contemptible."