noun
secrets; mysteries; hidden depths
Refers to profound, hidden truths or esoteric knowledge, often in spiritual, artistic, or technical contexts. Somewhat literary.
彼は武道の秘奥を極めるために修行を続けた。
He continued his training to master the hidden depths of martial arts.
この書物には人生の秘奥が記されている。
This book records the mysteries of life.