Definitions for "Insider Dealing"
buying or selling shares when in possession of privileged information that affects the price (e.g. while working for the company or an investment bank).
Insider Dealing is illegal share dealing on the basis of sensitive business data More Insurance - Insurance : Financial Glossary at 1Stop Finance (UK) More
This is when you buy or sell a share and at the same time possess privileged information that would move the price if it were widely known. It's illegal, but is also widespread and there are few prosecutions for it.