1. excellent understanding of sth, in-depth knowledge
a keen/deep insight into the situation/circumstances/problem
To have a keen or deep insight is to have a deep understanding or knowledge of a topic or subject. To be 'keen' means to like something or have an interest in it, or an aptitude for it: "He wrote about the struggles of the working class with keen insight." "The documentary will leave you with a deep insight into the struggles of the aboriginal community." These are formal phrases you will hear more commonly in educational or professional contexts.