keep one's counsel

verb2

1. •
   To keep one's own business private; to be careful, circumspect, or discreet in what one says concerning one's own deeds, situation, or thoughts.

   • As he held his mother to him, he longed to tell her all, but he kept his counsel. — 1848
2. •
   To keep a secret for someone else; to be careful, circumspect, or discreet in what one says concerning someone else's deeds, situation, or thoughts.

   • Standish will keep our counsel, and the news will be old before it's known. — 1871