adj.偷偷摸摸的，秘密的，趁人不注意赶紧进行的

He took a surreptitious look at his watch.
他暗暗看了一下手表。
They had several surreptitious conversations.
他们有过几次秘密会谈。
He was surreptitious in his movements.
他行踪诡异
He was caught red-handed, trying to surreptitiously slip out of the room without being noticed.
他被当场抓住，试图偷偷溜出房间而不被人察觉。
The thief made a surreptitious move to steal the valuable painting from the gallery.
那个小偷悄悄地试图从画廊偷走那幅珍贵的画作。
She sent a surreptitious text message to her friend during the meeting, trying not to be seen.
她在会议中悄悄给朋友发了一条短信，尽量不引起注意。
The spy's surreptitious surveillance on the enemy's headquarters proved invaluable.
间谍对敌方指挥部的秘密监控提供了极其宝贵的情报。
The children were surreptitiously playing hide-and-seek in the abandoned house.
孩子们在废弃的房子中秘密玩起了捉迷藏游戏。
He performed a surreptitious background check on his new colleague before they started working together.
在开始合作之前，他偷偷对新同事进行了背景调查。
Her husband's surreptitious phone calls became a source of constant suspicion and tension in their marriage.
她丈夫的秘密电话成了他们婚姻中的不安因素和紧张来源。
The gardener's surreptitious pruning of the shrubs surprised everyone, as they had no idea he was doing it.
园丁对灌木丛的隐秘修剪让所有人都感到意外，因为他们都不知道他在做什么。
The journalist managed to obtain surreptitious access to the top-secret government facility.
记者设法秘密进入了绝密的政府设施。
She wrote a surreptitious letter, expressing her feelings she couldn't openly share with her family.
她写了一封私密的信，表达了她无法公开与家人分享的感情。