noun
innermost depths; recesses
Formal or literary term for the deepest, most hidden part of the mind, heart, or abstract space. Often used in psychological or philosophical contexts.
彼の言葉は心の内奥に響いた。
His words resonated in the depths of my heart.
その小説は人間の内奥を描いている。
That novel depicts the innermost recesses of human beings.
Compound of 内 (inside) and 奥 (interior, depths). The exact historical derivation is uncertain, but the combination naturally conveys the idea of the innermost part.