on the sly

• Expresión informal que significa hacer algo en secreto, ocultamente o de manera que se evite llamar la atención de los demás.

An informal expression meaning doing something secretly, stealthily, or in a way that avoids being noticed by others.

1. Secretly or stealthilyB2informal

   Doing something in a secret or hidden way, often to avoid being noticed or caught.

   a escondidas

   • He was eating sweets on the sly, even though his doctor told him to avoid sugar.
   • She took a nap on the sly during the long meeting.
   • They were passing notes to each other on the sly in class.