Everyone is familiar with a situation where your conversation partner mentions an idea or a topic that you just can't stop thinking about for days without end.

To quote an economist Robert Lucas Jr.

Is there some action a government could take that would lead the economy to grow[...] once one starts to think about them, it is hard to think about anything else.

In my mother tongue (Slovak), there is a phrase for such an experience, literally translated as "planting a worm in someone's head".

Is there any such phrase/idiom in English?

Planting an idea is a very close substitute, but it communicates a (usually malicious) intent in doing so.

  • 3
    I keep thinking of earworm, but that's for a song that you can't get out of your head. I'm pretty sure there's something similar for an idea.
    – Barmar
    Feb 13, 2017 at 21:13
  • 2
    We do say "you put a bug in my head" and now I am obsessed. Feb 13, 2017 at 21:23
  • As others have noted, English does have the idiom "plant an earworm (in someone's head), but it almost always refers to music. For example, I can plant an earworm by humming a few notes, or simply asking you, straight up, who said that every wish, would be heard and answered, if wished on the morning star?
    – cobaltduck
    Feb 13, 2017 at 21:44
  • 1
    And of course, in the movie Inception, the protagonists pretty literally do this. Feb 13, 2017 at 22:26
  • 1
    looks pretty close to a duplicate of this one: english.stackexchange.com/questions/186670/… ALSO I would suggest PLANT an Idea in someone's mind. For what it's worth.. I'm not familiar with the "earworm" people are speaking about.. I live in CA
    – Tom22
    Feb 13, 2017 at 23:11

2 Answers 2


idée fixe "refers to an idea that dominates one's mind especially for a prolonged period"

According to The New Grove Dictionary of Music and Musicians, the term "idée fixe" was coined by French composer Hector Berlioz in 1830, who used it to describe the principal theme of his Symphonie fantastique. That reference goes on to say that, at about the same time, French novelist Honore de Balzac used "idée fixe" in Gobseck to describe an obsessive idea. By 1836, Balzac's more generalized use of the term had carried over into English, where "idée fixe" was embraced as a clinical and literary term for a persistent preoccupation or delusional idea that dominates a person's mind. Nowadays "idée fixe" is also applied to milder and more pedestrian obsessions. - from Merriam-Webster


Such an idea is sometimes called food for thought.


[Wordnet 3.0]
food for thought NOUN

  1. anything that provides mental stimulus for thinking
  • +1 "food for thought" is the phrase I would use in a day to day conversation, even though it doesn't convey the exact same meaning. On the other hand, it is virtually guaranteed to be understood. Feb 15, 2017 at 8:16

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