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.
The two of them talked frankly, opening up to each other.
He opened his heart and spoke his true feelings.
It is important to have a heart-to-heart talk, baring one's true feelings.
心中 is a formal word for what is in one's heart at a given moment, while 胸襟 specifically evokes the image of opening or baring that heart to another person.
内心 refers to one's private inner thoughts or feelings, while 胸襟 emphasizes the act of revealing those feelings to someone else.
心情 is a neutral, formal term for one's emotional state, while 胸襟 carries a literary, almost poetic connotation of the heart as something to be opened.
心 is the everyday word for heart or mind, while 胸襟 is a formal literary term used mainly in set phrases like 胸襟を開く.
胸中 describes what is currently in one's heart or mind, whereas 胸襟 is used specifically in phrases about opening one's heart to another person.
Compound of 胸 (chest, heart) and 襟 (collar, neck). Figuratively refers to the area near the heart, symbolizing one's inner thoughts and feelings.