Nadir Nadir The nadir (, ; from / ALA-LC: "naẓīr", meaning "counterpart") is the direction pointing directly "below" a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface there. Since the concept of "being below" is itself somewhat vague, scientists define the nadir in more rigorous terms. Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the nadir at a given point is the local vertical direction pointing in the direction of the force of gravity at that location. The direction opposite the nadir is the zenith. Nadir is
Opposite (semantics) has no word that stands in opposition to it (hence the unanswerability of "What is the opposite of platypus?"). Other words are opposable but have an accidental gap in a given language's lexicon. For example, the word "devout" lacks a lexical opposite, but it is fairly easy to conceptualize a parameter of devoutness where "devout" lies at the positive pole with a missing member at the negative pole. Opposites of such words can nevertheless sometimes be formed with the prefixes "un-" or "non-", with varying degrees of naturalness. For example, the word "undevout" appears in Webster's dictionary of 1828, while