Intelligence. What does it mean? The word "intelligence" has two main meanings in English. First, it can mean "mental capacity" – if you are intelligent, you can think clearly and rationally, for example. But "intelligence" also means information. For example, we can talk about "market intelligence" – and that means, information about what is happening in a market, such as the stock market or the international oil market. Very often, we use "intelligence" to mean information which is secret, or which has been obtained illegally.