Noun

1. A sight or view of the interior of anything; a deep inspection or view; introspection; frequently used with into.
   • 1980, Carl Sagan, Cosmos: A Personal Voyage,

     The history of our study of our solar system shows us clearly that accepted and conventional ideas are often wrong, and that fundamental insights can arise from the most unexpected sources.

2. Power of acute observation and deduction; penetration; discernment; perception.
3. Knowledge (usually derived from consumer understanding) that a company applies in order to make a product or brand perform better and be more appealing to customers
4. The act or result of apprehending the inner nature of things or of seeing intuitively
5. An extended understanding of a subject resulting from identification of relationships and behaviors within a model, context, or scenario.