Definition of: deep

(dēp) adjective
1. Extending or situated far, or comparatively far, below the surface.
2. Extending or entering far back, in, or away from the spectator's point of view.
3. Having a depth, thickness, dimension, or quantity measured from above downward, from before backward, or from without inward.
4. Profound in nature, reach, or degree.
5. Hard to understand or fathom because abstruse, complex, or well concealed.
6. Of great and well–trained or far–reaching intellectual powers; sagacious; penetrating.
7. Of great intensity; great in degree; extreme; hence, heartfelt and earnest.
8. Artful in the concealment of plans or schemes; insidious; scheming; designing.
9. Of low, sonorous, or heavy tone; grave.
10. Of intense or dark hue.
11. Immersed; absorbed: deep in a book.
—noun
1. A place or thing that has great depth; deep water; an abyss; especially, the sea or ocean.
2. Something too profound, vast, or abstruse to be easily comprehended; a mystery.
3. The most profound part; culmination: the deep of night.
4. Naut. The interval between two successive marked fathoms on a lead line or sounding line of a vessel.
—adverb
1. Deeply.
2. Far on, in reference to time. [OE dēop. Akin to DIP.]
—deep′ness noun