Under the radar — Doing something without attracting attention or being noticed; operating quietly so as to escape detection, scrutiny, or public awareness.
Origin & History
The phrase comes from military aviation. Radar systems, developed and rapidly improved during the Second World War, could detect approaching aircraft at a distance. Because radar coverage struggled to track objects flying very low to the ground, pilots learned to fly "under the radar" — beneath its detection range — to slip past enemy defences unseen.
From the late 20th century the expression was borrowed figuratively into everyday English. It came to describe anything — a person, a company, an activity — that operates quietly and escapes notice, completely detached from its original military and technical context.
Example Sentences
| Sentence | Context |
|---|---|
| The small startup flew under the radar for years before suddenly becoming a household name. | Business success unnoticed |
| He kept his side project under the radar until it was ready to launch. | Keeping plans private |
| The new policy slipped under the radar and few people noticed the change. | Unnoticed change |
| She prefers to stay under the radar rather than seek the spotlight. | Personal preference |
| Several minor bugs flew under the radar until users started complaining. | Overlooked problems |
| The band stayed under the radar for a decade before their breakthrough album. | Music industry |
How to Use It
This idiom works in both informal conversation and semi-formal contexts such as business writing and journalism. It is often paired with verbs of movement or staying, as in fly under the radar, stay under the radar, or slip under the radar. It can carry a neutral or slightly positive sense (deliberately discreet) or a negative one (something that wrongly went unnoticed), so let the context guide your meaning.
Common Mistakes
Mistakes to Avoid
The company stayed below the radars for years.
The company stayed under the radar for years. — Use the singular 'radar', not 'radars'; the noun is fixed.
He kept the project on the radar to avoid attention.
He kept the project under the radar to avoid attention. — 'On the radar' means the opposite: noticed and being watched.
She went under a radar after the scandal.
She went under the radar after the scandal. — Always use 'the', not 'a'; the article is fixed.
Similar Idioms
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