not made known or disclosed

अनजान

English Usage: The unrevealed secrets of the ancient civilization fascinated archaeologists.

Hindi Usage: प्राचीन सभ्यता के अनजान रहस्य पुरातत्वविदों का ध्यान खींचते हैं।

to keep something hidden or concealed

छुपाया हुआ

English Usage: The information remained unrevealed despite numerous inquiries.

Hindi Usage: कई पूछताछ के बावजूद जानकारी छुपाई हुई बनी रही।