The phrase "sealed lips" means to keep quiet or not reveal something that is supposed to be kept confidential.
Sentences with «sealed lips»
But alas, none of these questions have been answered yet, because with sealed lips the developers gave us a beautiful, artistic trailer and walked away. (coin-drop.com)
Most importantly, ask your kids to seal their lips for a few minutes. (indabaa.com)
Both Speaker of the House of Representatives, Yakubu Dogara and his predecessor and Governor of Sokoto State Aminu Tambuwal kept sealed lips on Tuesday as they emerged from a closed meeting with President Muhammadu Buhari. (nigeriapoliticsonline.com)