Definition of deep

• superl. - Extending far below the surface; of great perpendicular dimension (measured from the surface downward, and distinguished from high, which is measured upward); far to the bottom; having a certain depth; as, a deep sea.
• superl. - Extending far back from the front or outer part; of great horizontal dimension (measured backward from the front or nearer part, mouth, etc.); as, a deep cave or recess or wound; a gallery ten seats deep; a company of soldiers six files deep.
• superl. - Low in situation; lying far below the general surface; as, a deep valley.
• superl. - Hard to penetrate or comprehend; profound; -- opposed to shallow or superficial; intricate; mysterious; not obvious; obscure; as, a deep subject or plot.
• superl. - Of penetrating or far-reaching intellect; not superficial; thoroughly skilled; sagacious; cunning.
• superl. - Profound; thorough; complete; unmixed; intense; heavy; heartfelt; as, deep distress; deep melancholy; deep horror.
• superl. - Strongly colored; dark; intense; not light or thin; as, deep blue or crimson.
• superl. - Of low tone; full-toned; not high or sharp; grave; heavy.
• superl. - Muddy; boggy; sandy; -- said of roads.
• adv. - To a great depth; with depth; far down; profoundly; deeply.
• n. - That which is deep, especially deep water, as the sea or ocean; an abyss; a great depth.
• n. - That which is profound, not easily fathomed, or incomprehensible; a moral or spiritual depth or abyss.