surreptitious

1. ADJ A surreptitious action is done secretly. 秘密的[ADV with v]

He made a surreptitious entrance to the club through the little door in the brick wall. 他从砖墙的小门偷偷进入俱乐部。

2. surreptitiouslyADV

Surreptitiously Mark looked at his watch. 马克偷偷看了看表。