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Synonyms

on the sly

Idioms  
  1. Furtively, secretly, as in She's always eating cookies on the sly. The adjective sly, which means “cunning” or “crafty,” is here used as a noun. [c. 1800]


Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

The math-proficiency analysis suggests it may be doing so on the sly.

From The Wall Street Journal Nov. 30, 2025

Opening the case, prosecutor Naeem Valli said Connolly also sent a message saying she intended to work her notice period as a childminder "on the sly" - despite being de-registered.

From BBC Oct. 17, 2024

He was paroled from detention but banned from work and national health insurance, though he worked on the sly until about eight years ago, when the government started to tighten controls over parolees.

From Los Angeles Times Jul. 24, 2023

You started taking hormones kind of on the sly for a couple of weeks before you even talked to your wife.

From Slate Jun. 2, 2023

So my plan was to sneak into the Keys on the sly and see what I might do behind the scenes.

From "Flush" by Carl Hiaasen

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