undetected

Word family

• detect
  verbB2
• detection
  nounB2
• detective
  nounB1
• detectable
  adjectiveC1
• detector
  nounB2

Synonym discussion

Sense: adjective/1

'Undetected', 'unnoticed', 'undiscovered', and 'unseen' all describe things that escape awareness, but they differ in scope. 'Unnoticed' is the broadest — anything that fails to draw attention (a typo, a change in weather, someone's absence) can go unnoticed. 'Undetected' adds a layer of active looking: a security breach or an illness can be undetected even when someone is actively searching. 'Undiscovered' implies that something exists and has not yet been found, often carrying a sense of potential (an undiscovered island, undiscovered talent). 'Unseen' is the most literal — not visually perceived (an unseen messenger, an unseen obstacle). In everyday use, a virus goes 'undetected' by tests, a small gift goes 'unnoticed' at a party, an old letter remains 'undiscovered' in a drawer, and a spider in the corner stays 'unseen' until someone turns on the light.

Etymology

Formed from the prefix 'un-' (meaning 'not') and 'detected', the past participle of 'detect'. 'Detect' comes from Latin 'detegere' — 'de-' (un-, off) + 'tegere' (to cover). So literally: 'not uncovered' or 'not revealed'. The word entered English through French 'détecter' in the 15th century, and 'undetected' appeared in the early 1800s.