undetectable

IPA/ˌʌndɪˈtektəbl/
KK[əndɪtˈɛktəbəl]IPA/ˌʌndɪˈtektəbl/

undetectable — adjective

  • undetectablepositive
  • more undetectablecomparative
  • most undetectablesuperlative

1. Something that is undetectable cannot be observed, discovered, or measured, even

1.adjectiveB2
Definition

Something that is undetectable cannot be observed, discovered, or measured, even when the right methods or instruments are used — for example, a virus that stays hidden in the body, or a sound too quiet for any microphone to pick up.

Example

The virus can remain undetectable in the body for years before symptoms appear.

pattern: undetectable in + location (body, system, environment)

Rodrigo used a special ink that was undetectable under normal light.

Common collocations
  • remain undetectable
  • virtually undetectable
  • almost undetectable
  • undetectable to the naked eye
  • undetectable levels
  • undetectable by standard tests
Synonyms
  • imperceptible

    focuses on being too slight or gradual for the senses; more about physical perception than deliberate searching

  • invisible

    limited to sight only; something invisible cannot be seen, but may be detectable by other means

  • hidden

    implies deliberate concealment or covering, whereas undetectable is about the result (cannot be found) not the intent

Antonyms
  • detectable

    the direct opposite — able to be noticed, found, or measured

  • obvious

    very easy to see or understand; a much stronger degree of noticeability

Grammar Patterns

undetectable to + observer

undetectable by + method/instrument

undetectable in + location/system

Usage Note

Frequently followed by a prepositional phrase beginning with 'to' (the observer) or 'by' (the method). The subject of the sentence is something that exists but cannot be perceived — it is not the same as saying something is absent or non-existent.

Common Mistakes

The small scratch on the table is undetectable' (when meaning no one has noticed it yet).
The small scratch on the table has not been noticed yet.
'undetectable' means it cannot be found even with deliberate effort, not simply that no one has spotted it.
Her sadness was undetectable' (vague).
Her sadness was undetectable to the other guests at the party.
'undetectable' most naturally pairs with a specific observer or method.

Word family

Synonym discussion

Sense: adjective/1

All three words describe something that escapes notice, but they differ in scope and implication. 'Undetectable' is the broadest — it applies to anything that cannot be found, seen, heard, or measured, even with deliberate effort or the right tools. 'Imperceptible' is narrower, focusing on sensory limits: a change so tiny that the eye or ear cannot register it, even without active searching. 'Invisible' refers only to sight — a sound can be undetectable but never invisible. 'Hidden' carries intent: someone or something deliberately put the object out of sight. A hidden file on a computer was placed there on purpose; an undetectable file may simply be too small or cleverly disguised to appear in a normal search. In everyday use, choose 'undetectable' when the key idea is that a search or test fails, 'imperceptible' when the senses themselves are too weak, 'invisible' when only vision is involved, and 'hidden' when concealment was intentional.

imperceptible ↗invisible ↗hidden ↗

Common collocations

Nouns

Adverbs

Phrases

  • undetectable to the naked eye
  • undetectable by standard methods

Prepositions

Etymology

LatinFrenchEnglish

Formed in English by adding the prefix 'un-' (meaning 'not') to 'detectable'. 'Detectable' comes from Latin 'detectus', the past participle of 'detegere' ('to uncover or disclose'), which itself blends 'de-' ('off, away') with 'tegere' ('to cover'). So the word's literal history is 'not able to be uncovered' — a fitting root for a word about things that stay hidden no matter how hard you look.

First known use

1863

1863, in the meaning defined above