I agree with Tommo and Dan. I would not recommend calling clients names, not even out of the client's hearing. It's better to get into the habit of being respectful about them at all times. The reason why I say this is, the more practice you have at automatically being neutral and respectful, the greater the likelihood a situation won't escalate and you won't feel crummy. The client's poor behavior will stand out as being her problem and not yours.

That said, though, I would like to add that some companies have policies on client relations; some do not ask their employees to put up with abuse and when a client gets abusive the call is transferred to someone higher up. You might want to find out now how your company prefers you handle problematic clients.

From my personal experience, I was able to calm many people with this reply: "Would you like to speak to my supervisor?" and at one place, because we had a formal complaint system in place: "Would you like to lodge a formal complaint? I can get you the forms."

In cases where you are taken by surprise (which was probably the part this caller enjoyed) you could have said "Excuse me, I need to place you on hold for a moment" to help you gather your thoughts.