on the sly

副詞

慣用表現

(idiomatic) Slyly, in an inconspicuous manner, so as not to be seen; secretly; stealthily.

日本語の意味

こっそりと / ひそかに / 内密に / 秘密裏に

She slipped into the kitchen on the sly to steal a midnight snack.

彼女は夜中にこっそり台所に忍び込み、夜食を盗もうとした。

意味（1）

(idiomatic) Slyly, in an inconspicuous manner, so as not to be seen; secretly; stealthily.

This diversion was enjoyed on the sly, and unknown to the ladies of the house.