The antonyms for the expression "not in sight" can vary depending on the context. In some cases, they may include phrases such as "visible," "observable," "apparent," or "detectable." Conversely, antonyms could include terms like "hidden," "obscured," "concealed," or "camouflaged" when describing something that is difficult to find or intentionally removed from view. Overall, the antonyms for "not in sight" are useful for describing the range of visible and invisible material surrounding us. They can provide critical insight into why something may be hard to locate or help communicate the presence or absence of a significant object, person or idea.