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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.

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

From The Wall Street Journal • Nov. 30, 2025

We were forbidden to speak Urdu, but my mother still taught us on the sly.

From New York Times • Mar. 1, 2024

Sometimes, developers bought up units on the sly, knowing that control over assessments and expenditures could come as soon as a majority.

From Slate • Aug. 4, 2021

A vivid and wryly-observed pop anthem, it sees Peters confronting an ex who badmouths her in public, but still calls her on the sly.

From BBC • Jun. 15, 2021

“They weren’t courtin’ on the sly or anything like that.

From "Cold Sassy Tree" by Olive Ann Burns

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