0 secretly, without anyone seeing or knowing:
an audiotape of the surreptitiously recorded conversation
He watched surreptitiously from the hallway, and what he saw and heard made him suspicious.
If you were surreptitiously checking football scores on your cell phone during Thanksgiving dinner, you're just the sort of person the company is looking for.
An audio CD of the surreptitiously recorded conversation arrived at the newspaper in a brown envelope with no return address.
Sometimes spyware is installed surreptitiously when a person visits a website.
They went undercover to surreptitiously film racers at the illegal events, recording faces and license plates.
Secondly, a man surreptitiously removes a £5 note from one's jacket pocket as one is walking down the street.
Structural effects on agency typically do not occur surreptitiously.
In this way we would surreptitiously be introducing the idea that the model is a perfect image of the phenomenon being examined.