I'm wondering if there is a word to describe something that cannot be seen with the naked eye.

'Microscopic' is the first that springs to mind, but this has too many 'science-y' connotations.
It also implies that the subject is very very tiny, whereas I need a word to describe an object that might not be visible for any reason, for example, it's very far away or is obscured.

'Invisible' is not appropriate as it implies that the subject possesses some sort of magical powers...

Is there a word or short phrase to describe an object that cannot be seen with the naked eye - for whatever reason?

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    An interesting question, but an example of the thing that cannot be seen would help a lot. 'With the naked eye' implies that it can be seen when using an (optical) instrument - e.g. Jupiter's satellites can't be seen with the naked eye, but can be seen through a telescope. That kind of thing? But this doesn't encompass the situation when the thing is obscured... Gamma rays are invisible, although there powers are more scientific than magical. I'd love to give answering this one a try, but I need an example.
    – Lucky
    Commented May 5, 2015 at 16:19
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    @Lucky The Pre-Raphaelite painter William Holman Hunt claimed to be able to see the moons of Jupiter with his naked eye, and proved it. Some say that is exactly what is wrong with his paintings, too. Commented May 5, 2015 at 19:41
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    If it can't be seen withe naked eye then it can only be seen by using either science or magic. Take your pick.
    – Hot Licks
    Commented May 6, 2015 at 1:28
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    unobservable springs to mind.
    – Jodrell
    Commented May 6, 2015 at 12:29
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    @WS2 Please post that as an answer. It's the only option that really makes sense in this context.
    – Lilienthal
    Commented May 7, 2015 at 9:56

11 Answers 11


A word to describe an object that might not be visible for any reason, i.e., it's very far away or obscured

Indiscernible or imperceptible (to the naked or unaided eye)

indiscernible adjective: difficult or impossible to discern or perceive; imperceptible; "an indiscernible increase in temperature." TFD indiscernible

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    Nice choice. The first thing I thought of when reading the question was an astronomical entity (star, nebula, galaxy, etc.) you can't see with the naked eye. Obviously, these things are quite massive, but they are incredibly distant and may be visible to the naked eye only under the right circumstances.
    – Paul Rowe
    Commented May 5, 2015 at 15:59
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    Imperceptible seems to be the word most on-target with what OP was requesting.
    – Kurt Tappe
    Commented May 5, 2015 at 19:24
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    I knew there was a word!! God that was frustrating! Thankyou very much, excellent suggestions! :)
    – user98041
    Commented May 6, 2015 at 7:49
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    I don't think this works at all. "Indiscernible" and "imperceptible" both refer to detection by all the senses. For example, suppose you are walking past a pond that contains a number of frogs. It's perfectly possible that those frogs are not naked-eye visible, due to distance, camouflage and being hidden in the reeds. But you can certainly discern/perceive their presence because they're making noise. Commented May 6, 2015 at 9:02
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    And if you're going to add the rider "to the naked eye" then you may as well just say "not visible to the naked eye". Commented May 6, 2015 at 9:05

You could just say "not visible". I agree that "invisible" has a connotation as being an inherent property of the object, either science fiction-y or magical. "Not visible" means exactly the same thing, but doesn't put the burden so squarely on the object itself - it could be dark out, underground, behind a wall, etc.


If you want to be as straightforward as possible, there's unseen:

not seen or able to be seen (Merriam-Webster)

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    Unseeable also.
    – ermanen
    Commented May 5, 2015 at 15:41
  • This appears to be a poor choice because the reason that it is unseen might be because no-one has looked, not because it can't be seen - while the definition includes the one sought after here, it is ambiguous whether that's what it means. Commented May 6, 2015 at 9:15

Undetectable is an option, but this generally also assumes that one cannot hear/smell it either.

Undetectable - not able to be perceived, noticed, or discovered

Collins Dictionary


Infinitesimal is a word that describes something that exists, but has no truly discernible mass.


  1. indefinitely or exceedingly small; minute

  2. immeasurably small; less than an assignable quantity


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    The question has already rejected "microscopic" on grounds that the non-visibility isn't necessarily due to being small. Commented May 6, 2015 at 9:03

I actually think that invisible is a great option. Yes, I get the connotation, but that doesn't mean that is a necessity for using the word. "Not visible" doesn't really hold the same meaning in general usage. Something behind me is not visible. The sun is not visible at noon if my eyes are closed.

Unseen is similar. I would expect unseen to also mean that something simply isn't being seen, currently, or has not been seen. The core of the Earth is unseen, but then there are trees in the rain forests that have remained unseen, but this does not denote that it cannot be seen.

Invisible can be qualified: invisible to the naked eye, invisible to mankind, invisible from Earth, et cetera.

  • Unseen does denote "not able to be seen," as well as the vaguer "not seen." See the definition quoted in my answer.
    – Nicole
    Commented May 5, 2015 at 18:25
  • @Nicole - I'm not saying that isn't a definition of the word, I'm simply stating that in common language usage, that seems to be the more obscure usage. Perhaps your experience with the word differs from mine - that could be regional, even. I would just not jump to unseen meaning "not able to be seen" unless there was such heavy context involved that it could also be replaced with a variety of other words. Commented May 5, 2015 at 18:29
  • Take for instance: Cockroaches, the unseen caretakers of your kitchen floor, are attracted to the crumbs left behind after an incredible party. That sentence, to my eye, uses unseen in it's most common possible form. Obviously cockroaches CAN be seen. But they often go unseen since they shy away from light and human activity. I would typically expect unseen to mean pretty much that. Commented May 5, 2015 at 18:29
  • In much the same way that unforeseen doesn't mean that something could not be predicted, but rather that it had not been so. Commented May 5, 2015 at 18:31
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    I believe that the OP wanted a word to describe something that needs aid to be seen.
    – HarryCBurn
    Commented May 6, 2015 at 18:41


Tending to elude capture, perception, comprehension, or memory


How about an object which cannot be seen by the naked eye.

  • Given that all one-word terms for this have strong and potentially inappropriate connotations, I suspect that this is the right choice...
    – ExOttoyuhr
    Commented May 27, 2015 at 22:15

A shape/figure/silhouette can be indistinct

Not clear or sharply defined

It refers to camouflaged/far away objects that cannot be seen or distinguished from their environment.


another word that might help is 'unresolvable'

This might be good in a scientific context as we think about being able to resolve and object or not depending on the wavelenght of light, diffraction size of the camera lens or eye...

... so one might say

not possible to resolve the object with the naked eye



Difficult to understand or make out; vague

[American Heritage® Dictionary of the English Language]

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    The word works, but your definition is the wrong one for this sense (and isn't referenced). Try AHDEL sense 1b. Commented May 27, 2015 at 22:46