I'm looking for a word to describe something that can be physically passed through like a ghost, mist, or a gas. Initially, I was thinking of the work transparent, but I feel like this is better used to describe something that is see through.

  • There are a lot of answers that say stuff like intangible or immaterial. Doesn't those mean it can't be touched? Is it what you're locking for?
    – nelomad
    Nov 17, 2016 at 0:54
  • in game secondlife.com such objects have phantom set to true
    – aeroson
    Nov 17, 2016 at 9:43
  • Presumably liquids would also fall into this category. Its not a single word, but the best term I can think of is "not solid". Nov 19, 2016 at 10:33

10 Answers 10


Borrowing from Carl Sagan's The Dragon in My Garage, which suggests this word for specters:

incorporeal - having no physical body or form

(Definition from Merriam-Webster.)

I have to take issue with permeable. A sieve is permeable, a sponge is permeable, but unless you're a molecule or a virus or something similarly small you can't pass through.

  • 6
    In technical writing, permeable is often modified to indicate what can/can't get through. The difference between a sponge and a sieve is one of degree, not kind...
    – John Feltz
    Nov 16, 2016 at 3:36
  • 3
    Technically, I agree with you, but it's not to easy to imagine a person passing through an ordinary sponge or sieve. Perhaps in sci-fi, where people have been miniaturized. Nov 16, 2016 at 5:23
  • +1 Much better. Ghosts are not sieves.
    – DCShannon
    Nov 17, 2016 at 0:44
  • Captures the essence of the matter in question. :-) Nov 17, 2016 at 13:12
  • A sieve is not permeable to people, so permeable is still the perfect match to the title of the question, though incorporeal matches some other qualities the body of the question details.
    – Jon Hanna
    Nov 18, 2016 at 17:09

How about ethereal or penetrable?


ethereal: lacking material substance

penetrable: allowing someone or something to pass through or enter : able to be penetrated

It's not hard to imagine passing through anything ethereal.

It would not be unreasonable to consider a ghost, gas, or mist penetrable, in fact infinitely so.

Note: @Drew mentioned penetrable in a comment.

  • +1, but would also add 'intangible', 'insubstantial', and/or 'impalpable', since they don't mean that there is no physical matter, just that solid objects can't interact physically with that matter in any significant way. Would remove 'ethereal' and avoid 'incorporeal', 'unsubstantial', and 'immaterial', since those imply the absence of physical matter - which works for ghost but not mist or gases.
    – Jeutnarg
    Nov 16, 2016 at 18:22
  • 5
    +1 for ethereal, since it seems to come up often in descriptions of ghosts.
    – Ghotir
    Nov 16, 2016 at 19:29

The word you're looking for is permeable.

Ghosts are permeable, a gauze curtain is permeable, a cloud is permeable.


allowing liquids or gases to pass through

  • 2
    That's the answer. In addition, something penetrable can be passed into (but not necessarily passed through).
    – Drew
    Nov 16, 2016 at 3:23
  • 12
    Good to know that ghosts are permeable. Do they have a pore size? Other properties of permeable materials? Tortuosity, perhaps? Nov 16, 2016 at 5:35
  • That would have been my answer too. +1. @RichardKayser, lol. Nov 16, 2016 at 5:50
  • 16
    It seems to me that the OP is looking for a word to describe the characteristic of ghosts, gases, and mists that allows objects to pass through them, not the property of materials that allow ghosts, gases, and mists, or liquids, to pass through them. Permeable is perfect for the latter, wrong for the former. Perhaps the OP can weigh in. Nov 16, 2016 at 13:24
  • 4
    -1, Something that is permeable can be passed through because there are (possibly tiny) holes, not because the matter doesn't stop movement. This seems completely wrong for a ghost.This describes a strainer or cheesecloth. The definition you linked specifically says "having pores or openings that permit liquids or gases to pass through"
    – DCShannon
    Nov 17, 2016 at 0:44

Permeable is a good word. But if you're looking for variety, I'd suggest intangible. In comics, some suprheroes(e.g. Martian Manhunter) have this super-power where objects and people can pass though them as if they don't exist, helping them to dodge bullets etc. It's referred to as Intangibility.

ɪnˈtan(d)ʒɪb(ə)l/ adjective

unable to be touched; not having physical presence.
"the moonlight made things seem intangible"

If the context is ghosts or other spiritual entities, you can also use words like spectral or incorporeal to convey the same meaning.

  • 2
    +1, despite saying permeable is good. Intangible is absolutely the right word for this. Came to this page to post that as an answer.
    – DCShannon
    Nov 17, 2016 at 0:45
  • I don't think permeable is a good fit, but intangible is the right word. Here's a link to TVTropes that shows it's used that way in fiction: tvtropes.org/pmwiki/pmwiki.php/Main/Intangibility Nov 17, 2016 at 20:41

To expand on @stevesliva answer:

Immaterial - TFD

  1. Having no material body or form.
  • 2
    Immaterial is a good fit to the request but it's perhaps more commonly used in the sense of definition 1 from your link: Of no importance or relevance; inconsequential or irrelevant. If you're going to use this word you need to make sure the context makes clear which sense you mean.
    – nekomatic
    Nov 17, 2016 at 9:07

As an IT guy, I feel compelled to add traversable

capable of being traversed

traverse: a. To travel or pass across, over, or through: a ship traversing a channel; light traversing a window.

Traversing is more broad than "passing through". Even if maybe it's not the exact meaning you are looking for, sometimes it can be the most appropiate word.

  • I was going to suggest transitable but this is much better. I think it it what I was looking for. Nov 17, 2016 at 6:58
  • I think it's a bad choice for a word here. Traversable merely suggests that you can travel through the length, breadth, height of an object. Not pass through as though the object itself didn't exist. You traverse through an array of elements because it's traversable. If the array was intangible or incorporeal or ethereal, you'd always hit a null pointer exception.
    – anotherDev
    Jun 18, 2021 at 14:23

A book I enjoyed years ago called Calling on Dragons, by Patricia C. Wrede, described a character that became "insubstantial", fitting your desired description exactly.

a : lacking substance or material nature - Merriam-Webster


fluid: it means gas or liquid.

"a substance that has no fixed shape and yields easily to external pressure; a gas or (especially) a liquid."


  • Hey downvoter, please give some reasoning. Nov 17, 2016 at 5:49
  • 1
    Not my downvote, but a ghost is not a fluid. The OP wants a term that applies to a weird mix of stuff. Nov 18, 2016 at 11:26

One other way you can reference such an object is as "medium":

The intervening substance through which sensory impressions are conveyed or physical forces are transmitted


  • While true that most intangible things are mediums (as air is a medium for sound and even the void is a medium for light), not every medium is intangible (a copper wire is very much tangible, and as your own definition states, a wall is a medium for the force of a wrecking ball) and accidentally being a medium for some sensory impression is not what defines a ghost's insubstantiality.
    – Zachiel
    Nov 19, 2016 at 15:35

You could use the word transpirable

This is defined by Dictionary.com as:

To emit or give off waste matter, watery vapor, etc., through the surface, as of the body or of leaves.


To escape, as moisture or odor (or "gas"), through or as if through pores.

Alternatively, you could use respirable (regarding ghosts or mists), as defined by the Merriam-Webster:

Fit for breathing; also: capable of being taken in by breathing.

Hope this helps :)

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