I am looking for idioms or informal/slang/colloquial expression for some people that make you think that they are able of building a skyscraper, constructing a spaceship, playing the piano better than Mozart or something very fancy that requires remarkable skills, but when it comes to practice they prove to be completely inadequate.

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    As I understand it you are looking for an idiom to describe a person who boasts excessively, not an idiom to describe the act? I am inclined to downvote all those answers that describe the act because they are not answering the actual question.
    – z7sg Ѫ
    Commented Sep 12, 2011 at 19:56

15 Answers 15


There are tons of them. There's a whole sub-genre based roughly off the phrase "all talk (and no substance)". These generally have the form "all X, no Y".

Others culled from synonyms on the wictionary link below include:

  • All bark and no bite.
  • All booster, no payload.
  • All bubbles, no bath.
  • All crown, no filling.
  • All foam, no beer.
  • All ham, no let. (For you fans of The Bard)
  • All hammer, no nail.
  • All icing, no cake.
  • All lime and salt, no tequila.
  • All mouth and no trousers. (A corruption of All mouth and trousers)
  • All shot, no powder.
  • All show, no go.
  • All sizzle and no steak.
  • All talk, no walk.
  • All wax and no wick. (Alternatively All wick and no wax)

My personal favorite from cattle country here in the USA is to say that a person is all hat and no cattle.

As a note to outsiders, for some people wearing a cowboy hat has become something of a cultural statement. Thus many people wear them who, if confronted with an actual cow, would have no clue which end the "moo" comes out.

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    Rephrased this (and made community wiki) in a desperate attempt to stave off the profusion of similar answers. If you have a favorite "All X no Y" saying, I think it would be easier to come by if you post it on the list above or as a comment here, rather than make another similar answer.
    – T.E.D.
    Commented Sep 13, 2011 at 14:27

I believe a good idiom that describes this situation is blowing your own trumpet.

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    P.S. I believe an idiom that gets close to describing situation 3 is when it rains, it pours.
    – Bill
    Commented Sep 12, 2011 at 0:15
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    Hmm, I'm not sure "blowing your own trumpet" means that you can't necessarily do what you say you can, though.
    – user10893
    Commented Sep 12, 2011 at 0:51
  • @simchona - You may have a point but, it's the closest that I could think of.
    – Bill
    Commented Sep 12, 2011 at 0:55
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    A variant of this is tooting your own horn.
    – grautur
    Commented Sep 12, 2011 at 3:23
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    Perhaps related: blowhard Commented Sep 12, 2011 at 19:36

All gong and no dinner.

All fur coat and no knickers.

  • Welcome to English Language & Usage, Barrie. I would invite you to edit your answer in order to flesh it out, to give it a bit more context. That would then give other users an incentive to vote, and an high-voted answer is more likely to attract the attention of the poster.
    – Eldroß
    Commented Sep 13, 2011 at 12:47
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    Actually, both these logically go with my answer, probably as a comment.
    – T.E.D.
    Commented Sep 13, 2011 at 14:05

When someone is said to be “full of hot air”, it means that he or she talks rather a lot about topics he or she doesn't really understand.


  • Or slightly more vulgarly, just "full of (bull)shit".
    – Noldorin
    Commented Sep 13, 2011 at 17:41

braggart would be an appropriate and pretty generic term for such a person. This word would be appropriate in a formal or informal context. (Note that the verb "to brag" is pretty much synonymous with "to boast", so this is a pretty direct noun formation.)

From the examples you give, I would probably use the adjectives delusional and arrogant (narcissistic if you want to sound pompous, or cocky in slang) to describe such a person. For the former, an appropriate idiom might be:

He/she is on crack.

or even,

What is he/she smoking?

both alluding to the use of mind-altering drugs (though not usually literally).


Because the person can't actually do what they say they can, you could say that they cannot put their money where their mouth is:

If someone puts their money where their mouth is, they back up their words with action.

  • This idiom has the meaning "Better do sth instead of talking about it" while I more needed an idiom to emphasize that sb is boasting about things they can't do. But it's a good one too. Commented Sep 12, 2011 at 1:22

What about "to have a big head"?

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    This is very apt; but it’s more common, I think, as the adjective big-headed.
    – PLL
    Commented Sep 12, 2011 at 22:11

I know you’re looking for a colloquial idiom, but there does actually exist a (rare) word that means this very thing: jactator. It’s a direct borrowing from the identical Latin word. The OED marks it as “obsolete rare-0”, with the last citation given from back in the 18th century.

Somewhat more current and less rare is the related term jactation, whose sense 2 is “Boasting, bragging, ostentatious display.” It is not marked as obsolete or rare, or even archaic. Here are that sense’s citations:

  • 1576     J. Woolton Christian Man. sig. H.iiiiv,     If wee vse them with excesse, fylthy pleasure, vaine iactation:‥we abuse Gods good gyftes.
  • 1604     T. Wright Passions of Minde (new ed.) i. vi. 26,     I could adde‥Envy, Emulation‥Iactation or Boasting.
  • 1825     London Mag. I. 379     There is no surer sign of vulgarity than jactation of gentility.
  • 1886     Saintsbury in Macmillan's Mag. July 171     The tedious burlesque, the more tedious jactation which disfigure his work.

Its pronuncation is /dʒækˈteɪʃən/ , and its entymology is:

Latin jactātiōn-em, n. of action from jactāre to throw, toss about, discuss, boast of, refl. to talk boastfully, make an ostentatious display, frequentative of jacĕre to throw; compare French jactation (Cotgrave).

I suspect that jactator has strong potential for all sorts of intentional misunderstandings in various wicked puns. :)

Probably only students of Latin or speakers of derived Romance tongues would understand its original meaning. For example, jactarse de algo is “to boast of something” in Spanish, and is a perfectly common use, not a rare one.

Google Ngrams shows scant but measurable use of jactator compared with somewhat more frequent use of jactation, which actually seems to be on the rise since 2000. It might be used in its pathology sense, though.


Scott Adams suggests "Topper".


Ten cent millionaire was my father's favorite expression for people who try to glorify themselves.

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    Welcome to ELU. It's a good idea to add further detail and reliable references to your answers.
    – Neeku
    Commented Oct 30, 2014 at 11:18

Some people can't walk the talk.

  • Or you might say the person, "Talks a big game." Commented Sep 12, 2011 at 19:34

One of my favorites: Blowhard


Braggart, blowhard, and the more vulgar bullshitter all work well in daily, idiomatic American English.


"A legend in his own mind" seems fitting...


grandiose 1 : characterized by affectation of grandeur or splendor or by absurd exaggeration Example: They did not believe his grandiose claims.

That fellow is grandiose; he told everyone he discovered the Fountain of Youth, but it was only a beer keg. I said, "You're joking!", but he was serious.

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