on the sly
US /ɑn ðə slaɪ/
UK /ɑn ðə slaɪ/
1.
a escondidas, en secreto, furtivamente
doing something secretly or furtively
:
•
He was eating cookies on the sly when his mom wasn't looking.
Estaba comiendo galletas a escondidas cuando su mamá no miraba.
•
They were meeting on the sly to plan the surprise party.
Se estaban reuniendo a escondidas para planear la fiesta sorpresa.
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