How to verify that the variable "does not contain" a value?

Hi

I am using CP 7.0.1.237.

We want to use Text Area widget for a custom quiz and verify an answer. While we figured out how to verify the existence of certain keywords, we are not able to figure out how to verify that the content should NOT contain certain keywords. For example, we want to ensure that the text entered in this widget should not contain "Transformation" and "Non-compliant".

Is this possible at all?

Thanks

Sreekanth