serious; severe; grave; acute
with profound (often hidden) meaning; pregnant with significance; meaningful; suggestive; interesting
deep sea; depths of the sea; ocean depths
deepest part; deepest portion; depths (of the ocean etc.); innermost
mountain recess; deep in the mountains
silent; still; quiet; hushed
profound; deep; unfathomable
esoteric doctrines; mysteries
deep psyche; unconscious mind; depth psychology
closeted maiden; carefully-raised girl from a well-to-do family
middle of the night; dead of night; midnight
becoming more serious or severe; aggravation; intensification
with profound (often hidden) meaning; pregnant with significance; meaningful; suggestive; interesting
far sight and deep design
silent (esp. of the passing of the night); piercing (cold)
late-night show; midnight broadcast
deliberate; careful; thoughtful; thoughtfulness; prudence
deliberate; careful; thoughtful; deeply laid plan
calm; composed; collected; silently (of the passing of the night); quietly
deep design and forethought; a farsighted and deeply-laid plan
profound; careful; mature
kind; gentle; considerate; generous; friendly; nice
loitering at night (between 11pm and 4am); late-night prowling
depth; shade (of color, colour)
deep appreciation or gratitude; sincere apology
deep ocean water; deep-sea water
to be brought up with tenderest care in a good family
extremely deep (i.e. profound)
deep learning; deep machine learning
deep vein thrombosis; DVT
deep design and forethought; farsighted and deeply-laid plan
deep autumn (when the autumn has reached its climax)
depth of field (photography)
deep plowing; deep ploughing
deep sadness; great worry
bathyesthesia; deep sensibility
intrusive igneous rock; plutonic rock
midnight express (train, bus)
deep earthquake; deep-focus earthquake
abyssal plain (2,200-5,500m)
deep water (depth: 2000-4000 meters)
nine shallow, one deep (ancient Chinese sexual technique)
deep geological disposal (of radioactive waste)
close classification system; depth classification system
subzero treatment; deep cooling; sub-zero cooling; sub-zero treatment
deep brain stimulation; DBS
deepest snow; maximum snowfall; maximum depth of snow cover
crouched walk treading on hands for stealth used by ninja
hadal zone; hadopelagic zone; trench zone
bathyal zone; midnight zone; bathypelagic
like looking out on an abyss; like standing on the edge of an abyss