Translation guide
The English word "deep" has several distinct meanings. This guide helps you choose the right Japanese expression based on whether you mean physical depth, profound thought, intense emotion, deep color, or other uses.
Describing something that extends far down from the surface, like a deep hole, deep water, or a deep container.
The most common and versatile adjective for physical depth. Can be used for holes, water, snow, etc.
This lake is very deep.
I dug a deep hole.
Noun meaning "depth." Use when talking about the measurement of depth.
How deep is this river? (lit. What is the depth of this river?)
Describing ideas, understanding, meaning, or thought that is not superficial; showing great knowledge or insight.
The same adjective 深い is used metaphorically for abstract depth. Very common for knowledge, understanding, meaning, etc.
He has deep knowledge.
A more formal or literary term meaning profound, deep, abstruse. Often used for philosophies or abstract concepts.
Literally "deep interior," implies something profound with many layers of meaning or complexity. Often used for arts or culture.
Describing strong feelings like love, gratitude, or a close bond.
Describing a color that is dark and rich, not pale.
Describing a state of sleep from which it is hard to wake.
Describing a low-pitched voice or sound.
Describing being completely focused on thinking or an activity, unaware of surroundings.
Verb meaning "to be deep in thought," often with a nuance of worry or pondering.
He is deep in thought about something.
To be absorbed or immersed in an activity. Use with に (e.g., 研究に没頭する).
She is deep in reading (absorbed in a book).
A formal, literary phrase meaning "deep in meditation" or "lost in thought."
He was deep in thought.
Describing something located far from the entrance or edge, like deep in the forest or deep in the mountains.
Noun meaning "interior" or "back." Used as 奥深く (deep into) or 奥の (deep/inner).
There is a cabin deep in the forest.
We went deep into the cave.
For colors, 濃い (koi) is the most natural choice for "deep" or "dark" shades. 深い (fukai) can be used but is less common and may sound slightly poetic. Use 濃い for everyday descriptions like deep red (濃い赤) or deep blue (濃い青).
Do not use 深い声 (fukai koe) for a deep voice; it sounds unnatural. Use 低い声 (hikui koe) for low pitch or 太い声 (futoi koe) for a rich, resonant voice.
The water is deep here.
He has a deep understanding of the subject.
She took a deep breath.
Those words have a deep meaning.
深遠な哲学の話だった。
It was a deep philosophical discussion.
Japanese culture is deep (has profound depth).
彼には厚い信頼を寄せている。
I have deep trust in him.
A deep green forest.
A deep voice echoed.