deep

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Extending far downward below a surface.
• adjective Extending far inward from an outer surface.
• adjective Extending far backward from front to rear.
• adjective Extending far from side to side from a center.
• adjective Far distant down or in.
• adjective Coming from or penetrating to a depth.
• adjective Sports Located or taking place near the outer boundaries of the area of play.
• adjective Extending a specific distance in a given direction.
• adjective Far distant in time or space.
• adjective Difficult to penetrate or understand; recondite.
• adjective Of a mysterious or obscure nature.
• adjective Very learned or intellectual; wise.
• adjective Exhibiting great cunning or craft.
• adjective Of a grave or extreme nature.
• adjective Very absorbed or involved.
• adjective Profound in quality or feeling.
• adjective Rich and intense in shade. Used of a color.
• adjective Low in pitch; resonant.
• adjective Covered or surrounded to a designated degree. Often used in combination.
• adjective Large in quantity or size; big.
• adjective Sports Having a sufficient number of capable reserve players.
• adverb To a great depth; deeply.
• adverb Well along in time; late.
• adverb Sports Close to the outer boundaries of the area of play.
• noun A deep place in land or in a body of water.
• noun A vast, immeasurable extent.
• noun The extent of encompassing time or space; firmament.
• noun The most intense or extreme part.
• noun The ocean.
• noun Nautical A distance estimated in fathoms between successive marks on a sounding line.
• idiom (deep down) At bottom; basically.
• idiom (in deep water) In difficulty.

from The Century Dictionary.

• Deeply.
• To become deep; deepen.
• To go deep; sink.
• Having considerable or great extension downward, or in a direction viewed as analogous with downward.
• As measured from the point of view: extending far above; lofty: as, a deep sky.
• As measured from without inward: extending or entering far within; situated far within or toward the center.
• As measured from the front backward: long: as, a deep house; a deep lot.
• Having (a certain) extension as measured from the surface downward or from the front backward: as, a mine 1,000 feet deep; a case 12 inches long and 3 inches deep; a house 40 feet deep; a file of soldiers six deep.
• Immersed; absorbed; engrossed; wholly occupied: as,deep in figures.
• Closely involved or implicated.
• Hard to get to the bottom or foundation of; difficult to penetrate or understand; not easily fathomed; profound; abstruse.
• Sagacious; penetrating; profound: as, a man of deep insight.
• Artful; contriving; plotting; insidious; designing: as, he is a deep schemer.
• Grave in sound; low in pitch: as, the deep tones of an organ.