"What's-what" is a phrase used to refer to specific knowledge or information about a particular subject. Synonyms for this phrase include "the lowdown," "the scoop," "the skinny," "the details," "the inside story," and "the nitty-gritty." All of these terms describe a deep level of understanding or familiarity with a given topic. They can be used in a variety of contexts, from casual conversation to more formal settings. Regardless of the word choice, they all convey the same idea: a comprehensive understanding of the subject at hand.
