slip beneath the/(one's) radar(redirected from slipped beneath their radar)
slip beneath the/(one's) radar
To go unnoticed or undetected (by someone). With so many different amendments to the bill being made, some appropriations slipped beneath the radar. As the manager of this office, it's inexcusable that you allowed embezzlement by an employee to slip beneath your radar.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.