What does the term "adrift" refer to?

The term "adrift" refers specifically to a situation where a vessel is floating without being secured or controlled, which aligns with the concept of being lost or out of control. When a boat or ship is adrift, it indicates that it is not anchored or tied up, leading to it being subject to the currents and tides, often resulting in a lack of navigational precision and security. This term is commonly used in maritime contexts to describe vessels that are not properly secured and could move with the water, potentially leading to unsafe situations.

The other choices represent conditions that imply secure handling and control of the vessel. For instance, being securely moored or docked safely signifies that a vessel is properly anchored or tied to a berth, allowing for stability and safety. Similarly, being in calm waters describes a tranquil environment but does not reflect the state of a vessel being unmoored or lacking control. Therefore, the context of "adrift" distinctly underscores the aspect of being lost or out of control, which is why that interpretation is correct.