transitive. to open one's heart: to reveal one's (esp. most intimate or private) feelings, thoughts, secrets, etc.; to reveal or confess everything…

†to break one's mind (heart): to deliver or reveal what is in one's mind (obsolete). to break news, to break a matter, to break a secret: to make…

to show one's mind: to reveal one's thought or intention; to express one's opinion or judgement. Also with forth. Now rare.

to utter (the bottom of) one's stomach: to disclose one's inmost thoughts. Similarly, to fish out the bottom of a person's stomach. Obsolete.

to utter (the bottom of) one's stomach: to disclose one's inmost thoughts. Similarly, to fish out the bottom of a person's stomach. Obsolete.

to show one's true colours and variants: to reveal one's real character, allegiance, or intentions, esp. when these are disreputable or dishonourable.

intransitive. With complement. To make a public declaration in support of or against something specified; to declare oneself a supporter of, or…

intransitive. To declare one's thoughts or feelings, to unburden oneself. Cf. senses 12d.

(out) in (also into) the open: openly; without concealment or obfuscation. to bring (out) in (also into) the open: to bring to public notice or…

reflexive and intransitive. To disclose what is in one's bosom, unburden oneself.

absol. To undo one's own buttons; also (quot. 1616), to become unbuttoned. Also figurative.

Business. Of a privately owned company: to make its shares available to be traded on a major stock exchange; to become a public company.