• 深夜しんや — late at night
• 深海しんかい — deep sea
• 深刻しんこく — serious, severe
• 深謝しんしゃ — deep gratitude
• 深緑しんりょく — deep green, dark green
• 深呼吸しんこきゅう — deep breath

深 is made up of the radical for water (氵) and the phonetic part ⟨⿱罙⟩, which hints at something sinking or being submerged. Together, they evoke the idea of depth — whether literal (like ocean depths) or figurative (like deep emotion or meaning).

深夜しんやまで勉強べんきょうしました。
I studied until late at night.

海うみの深ふかさに驚おどろきました。
I was amazed by the depth of the sea.