彼は密かに計画を進めていた。
He was secretly pressing ahead with his plan.
彼女は密かに同僚に思いを寄せている。
She secretly has feelings for a coworker.
二人は夜のうちに密かに町を抜け出した。
The two of them slipped out of town quietly during the night.
優勝を密かな目標にして練習を続けてきた。
I have kept practicing with winning the title as my private goal.