covertly
adv. 秘密地;偷偷摸摸地
例句
They covertly observed Lauren, who was sitting between Ned and Algie at a nearby table.
他们秘密地观察着邻近桌子上坐在内德和阿尔吉之间的罗伦。
《柯林斯英汉双解大词典》
She watched him covertly in the mirror.
她从镜子里偷偷地望着他。
《牛津词典》
But the Forster in both these books comes across as covertly sophisticated.
这两本书中的福斯特让人觉得捉摸不定、老于世故。