Obscure, mysterious.
Understood by only a few.
Extremely old (e.g. interpretation or knowledge), and possibly irrelevant.
Requiring secret or mysterious knowledge to understand.
Hard to penetrate or comprehend; profound; intricate; obscure.
In a (specified) number of rows or layers.
Positioned or reaching far, especially down through something or into something.
Voluminous.
Far in extent in another (non-downwards, but generally also non-upwards) direction away from a point of reference.
Low in pitch.
Far from the center of the playing area, near to the boundary of the playing area, either in absolute terms or relative to a point of reference.
Distant in the past, ancient.
Significant, not superficial, in extent.
Muddy; boggy; sandy; said of roads.
Extending far down from the top, or surface, to the bottom, literally or figuratively.
Penetrating a long way, especially a long way forward.
Positioned back, or downfield, towards one's own goal, or towards or behind one's baseline or similar reference point.
Thick.
Profound, having great meaning or import, but possibly obscure or not obvious.
Extending to a level or length equivalent to the stated thing.
Highly saturated; rich.
Sound, heavy (describing a state of sleep from which one is not easily awoken).
Of penetrating or far-reaching intellect; not superficial; thoroughly skilled; sagacious; cunning.
A deep hole or pit, a water well; an abyss.
A deep shade of colour.
A silent time; quiet isolation.
The deep part of a lake, sea, etc.
The profound part of a problem.
A fielding position near the boundary.
The sea, the ocean.
In a profound, not superficial, manner.
In large volume.
Back towards one's own goal, baseline, or similar.
Far, especially far down through something or into something, physically or figuratively.