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.
この湖はとても深い。
This lake is very deep.
深い穴を掘った。
I dug a deep hole.
Noun meaning "depth." Use when talking about the measurement of depth.
この川の深さはどれくらいですか。
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.
彼は深い知識を持っている。
He has deep knowledge.
その言葉には深い意味がある。
Those words have a deep meaning.
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.
The standard adjective for deep or dark colors. Also means "thick" or "dense" for liquids.
彼女は濃い青のドレスを着ていた。
She wore a deep blue dress.
Can also be used for deep colors, but 濃い is more common and natural for color depth.
Describing a state of sleep from which it is hard to wake.
Describing a low-pitched voice or sound.
The standard adjective for low pitch. Use 低い声 for a deep voice.
彼は低い声で話した。
He spoke in a deep voice.
Literally "thick," can describe a deep, resonant voice, especially for men.
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.
彼は何かを考え込んでいる。
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).
彼女は読書に没頭している。
She is deep in reading (absorbed in a book).
A formal, literary phrase meaning "deep in meditation" or "lost in thought."
彼は沈思黙考していた。
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).
森の奥深くに小屋がある。
There is a cabin deep in the forest.
洞窟の奥まで進んだ。
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.
ここは水が深い。
The water is deep here.
彼はそのテーマについて深い理解がある。
He has a deep understanding of the subject.
彼女は深く息を吸った。
She took a deep breath.
深遠な哲学の話だった。
It was a deep philosophical discussion.
日本の文化は奥深い。
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.