slyness
sly
noun
uk /slaɪ/ us /slaɪ/
 on the sly
If you do something on the sly, you do it secretly because you should not be doing it: 暗中，偷偷地
He drives his mother's car on the sly while she's at work.他在母亲上班的时候偷开她的汽车。

sly | American Dictionary

sly
adjective
us/slɑɪ/comparativeslyer | superlativeslyest
not letting others know true opinions or intentions, or dishonest:
She thought that by being sly, she could fool people.
A cat can be a very sly animal.

slyly

adverbus/ˈslɑɪ·li/
He winked slyly and lowered his voice, as if he had some secret to reveal.

Examples of sly

sly
He is extremely sly and duplicitous with those around him.
Meanwhile, the upand-coming wave the colon's limp magic wand, without a sly joke to tell.
As it is, there is much to admire, whether in sheer compositional dexterity or in the composer's sometimes sly sense of humour.
There's a sly sense of disruptive humour not far from the surface, too.
They employed, instead, sly ambiguities and insinuating circumlocutions.
The editorial voice, assumed at this point by the narrator, carries a sly irony of its own.
Because human is the spirit of all things on earth, he is therefore very sly.
Historians seem to feel obliged to place a sly construction on all his operations, for fear of being branded naive.
Examples may be found from bar 144 in the sweep of both string parts, with their independent accents, or in the cello's sly comments from bars 161 to 165.
Anyone who makes a sly or fast buck, who seeks to cheat or to deceive must pay the full penalty of the law, and quickly.
From the
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