verb (used with object)

to discover or catch (a person) in the performance of some act: to detect someone cheating.
to discover the existence of: to detect the odor of gas.
to find out the true character or activity of: to detect a spy.
  1. to rectify alternating signal currents in a radio receiver.
  2. to demodulate.

Origin of detect

1400–50; late Middle English < Latin dētēctus (past participle of dētegere), equivalent to dē- de- + teg(ere) to cover + -tus past participle suffix
Related formsde·tect·a·ble, de·tect·i·ble, adjectivede·tect·a·bil·i·ty, de·tect·i·bil·i·ty, nounpre·de·tect, verb (used with object)un·de·tect·a·ble, adjectiveun·de·tect·a·bly, adverbun·de·tect·ed, adjectiveun·de·tect·i·ble, adjective

Synonym study

2. See learn. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for undetectable

Contemporary Examples of undetectable

Historical Examples of undetectable

  • He'd broken through the screen of guard-ships in undetectable overdrive.

    Pariah Planet

    Murray Leinster

  • They would be undetectable by normal telepathic means, you know.


    Everett B. Cole

  • It is undetectable and invisible--your detectors do not touch it and light-waves are bent around it without loss or distortion.


    Edward Elmer Smith

  • Monday morning Tom buckled down seriously to the job of designing an undetectable sub.

  • Those enemies of ours are clever, but if they can produce an undetectable sub, there's no reason why I can't do the same.

British Dictionary definitions for undetectable


verb (tr)

to perceive or noticeto detect a note of sarcasm
to discover the existence or presence of (esp something likely to elude observation)to detect alcohol in the blood
to extract information from (an electromagnetic wave)
obsolete to reveal or expose (a crime, criminal, etc)
Derived Formsdetectable or detectible, adjectivedetecter, noun

Word Origin for detect

C15: from Latin dētectus uncovered, from dētegere to uncover, from de- + tegere to cover
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for undetectable



early 15c., from Latin detectus, past participle of detegere "uncover, expose," figuratively "discover, reveal, disclose," from de- "un-, off" (see de-) + tegere "to cover" (see stegosaurus). Related: Detected; detecting.

Online Etymology Dictionary, © 2010 Douglas Harper