To describe something is to tell or depict it in written or spoken words: He described the accident very carefully. The synonym portray suggests a more graphic or vivid accounting of events. This term, as you might’ve guessed, has an artistic heritage; its earliest use in English was to mean “to make a likeness of by drawing, painting, or carving.” This brings into focus portray’s connection to such words as portrait and portraiture. When you portray something, you’re not just recounting it; you’re attempting to paint a picture with words! More theatrically, portray means “to represent dramatically,” as an actor might represent a historical figure on the stage.
The adjective essential is used to describe things that are absolutely necessary for a particular purpose. For example, discipline is essential in an army. This all-important descriptor is related to the noun essence, which is defined as “the basic, real, and invariable nature of a thing.” Indeed, sometimes essential suggests that which is in the very essence of constitution of a thing: Oxygen and hydrogen are essential in water. The synonym indispensable is a strong synonym for essential: it is used to describe people or things that are absolutely necessary or requisite—in other words, people or things that cannot be done without: She was an indispensable member of the staff.
The adjective secret is used to describe things that are either done without the knowledge of others, such as secret negotiations, or that are working to escape notice or observation, such as secret police. It’s also used to describe things that are secluded or sheltered, such as a secret hiding place—and things that are known by only a few, such as a secret password. The synonym clandestine is used to describe operations, meetings, and programs that are done in or executed with concealment, especially for the purposes of subversion or deception. If you’re looking to describe the activities of international spies or stealth programs run by the military or a government, clandestine is the perfect choice.