noun
one's heart; one's true feelings; bosom
Literary and somewhat formal; often used in expressions like 胸襟を開く (to open one's heart) or 胸襟を披く (to bare one's heart). Not used for the physical organ.
彼は胸襟を開いて本音を語った。
He opened his heart and spoke his true feelings.
胸襟を披いて話し合うことが大切だ。
It is important to have a heart-to-heart talk, baring one's true feelings.