Rashi (from Shocher Tov 6): He pretends to be pained [over my illness], but while he is in front of me, he has sinful thoughts of what evil he will speak, and when he leaves, he says it.

Radak citing his father: Whether he speaks softly or harshly, it is to break my heart. E.g. one visited a Choleh, and said 'your illness is harsh to me - my father died from it!'

Malbim: If one of them tells them that they speak falsely (that I will die from my illness), when he comes to see me, to see the Emes, and he sees that I am alive, and fears lest I be cured, he plots how to kill me. When he goes outside, he tells them.

Rashi (from Shocher Tov 6): While he is in front of me, he thinks about what evil he will speak, and when he leaves, he says it.

Radak: In front of me, he gathers his evil; he does not say it with his lips. When he goes outside, he tells others the evil that was gathered in his heart.

Malbim: Refer to 41:7:1:3.