In plain English
Verbosity describes how much a model says when it answers. A concise response might give a direct answer, while a more verbose one adds explanations, examples, and background. A prompt can request a brief or detailed response. More words do not necessarily mean a better answer or more reasoning.
Example
A startup founder asks an AI assistant to explain a monthly sales report. A low-verbosity response gives a short summary, while a high-verbosity response walks through each metric with explanations and examples.