(with "the") The deep part of a lake, sea, etc.
creatures of the deep
(with "the") A silent time; quiet isolation.
the deep of night
A deep shade of colour.
The profound part of a problem.
(with "the") The sea, the ocean.
A fielding position near the boundary.
Russell is a safe pair of hands in the deep.
(of a physical distance) Extending far away from a point of reference, especially downwards.
(intellectual, social) Complex, involved.
(sound, voice) Low in pitch.
She has a very deep contralto voice.
(of a color) Highly saturated.
That's a very deep shade of blue.
(sleep) Sound, heavy (describing a state of sleep from which one is not easily awoken).
He was in a deep sleep.
Immersed, submerged (in).
deep in debt
Muddy; boggy; sandy; said of roads.
(of time) Distant in the past, ancient.
deep time
Deeply.