under (the/one's) radar

Without being noticed, detected, or addressed. A: "Have you heard this band's latest album?" B: "I didn't even know it was out, it must have flown under my radar." Every year, the government promises to do something about the homelessness problem, yet every year it seems to slip under the radar again.

In a position in which someone or something will remain unnoticed or undetected. With so many different amendments to the bill being made, some appropriations slipped under the radar. I plan to stay under the radar until this controversy blows over.

Describing an action that cannot be detected. The term comes from aviation during World War II, where a plane is flying too low to be detected by the enemy’s radar. It soon was transferred to other situations, as in “I don’t want anyone to know I’m looking for another job, so keep my applications under the radar.” John Lescroart used it in A Plague of Secrets (2010), “Now I know . . . it hasn’t been the subject of much police concern so far . . . So up to now you’re all under the radar.”