off the radar

off the radar

Unseen or undetected for a long time. Mr. Smith has gone off the radar since his wife died, so I'm going to stop by his house this afternoon and check on him. That rebel group's operations have been completely off the radar for years—I worry we'll never be able to find them.
See also: off, radar

on/off the ˈradar (screen)

used to say that people are aware or not aware of something, or are thinking or not thinking about it: Foreign policy is just not on most people’s radar screens.Eastern Europe has remained off the radar of most UK investors.
See also: off, on, radar