pulling in one's horns

Verb

pull in one's horns (third-person singular simple present pulls in one's horns, present participle pulling in one's horns, simple past and past participle pulled in one's horns)

1. (idiomatic) To become less impassioned, aggressive, or argumentative; to exercise restraint; to yield or capitulate.
   • Barry . . . stood, during this tirade, half stupefied with rage, and half frightened, at the open attack made on him. . . . However, he couldn't pull in his horns now, and he was obliged, in self-defence, to brazen it out.1848, Anthony Trollope, chapter 7, in The Kellys and the O'Kellys

   Synonyms:

   calm down, chill, chill out, cool off, cool one's jets, hold one's horses, settle down