adjective / adverb / noun
deep
DEEP/diːp/
Extending far beneath a surface or into a space.
The narrow well is deep, extending far below the ground.

Etymology
Old English deop described distance below a surface and already also meant “profound.” That pairing connects physical depth with intellectual depth: reaching far into a subject rather than remaining at its surface.
In context
the deep sea is without a doubt alien to us this great void extending far beneath the surface
More examples
- This deep drawer holds all our largest pots.
- The tree's roots reach deep into the soil.
- Whales rise from the deep to breathe.
Forms
deep · deeper · deepest · deeps
depth noun — Distance below a surface or inward.
deepen verb — To make or become physically deeper.
Similar words
- bottomless
- Suggests no reachable bottom, rather than simply great depth.