gizlice, caktirmadan

listen to the pronunciation of gizlice, caktirmadan
Турецкий язык - Английский Язык
(deyim) on the sly
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.

furtively: in a furtive manner; "the soldiers were furtively crawling through the night"
stealthily, in a sneaky manner