Glossary Home Idioms

Not playing with a full deck

“Not playing with a full deck” is a way of saying that someone is mentally unsound or unintelligent.

“Not playing with a full deck” is a great example of a phrase that takes context to understand. Knowing its individual words does not mean that one is going to know what the phrase itself means. Idioms are defined by their complicated meanings and the fact that they allude to something different than they literally state. 

Not playing with a full deck idiom


Meaning of “Not playing with a full deck”

“Not playing with a full deck” is a way of saying that someone is mentally, intellectually, or psychologically deficient in some way. When someone uses the phrase they’re using a type of euphemism, or a saying that replaces one statement with another that’s more palatable. Rather than say “I don’t think they’re very smart” someone might say “I don’t think they’re playing with a full deck,” or a “full deck of cards.” The phrase is most commonly used in jest, to poke fun at someone. But, it can be used more cruelly in order to suggest that someone is truly mentally unsound. It’s a way of saying that someone doesn’t have all the necessary thought processes needed in order to complete something successfully. 


When To Use “Not playing with a full deck”

It’s possible to use “not playing with a full deck” in a variety of situations. It is best used among family, friends, and close colleagues. It is inappropriate for professional situations, such as meetings or speeches. One would not expect to hear to phrase in an academic paper or from one’s boss/manager. If one used it in one of these settings one would likely be scolded or at least make their colleagues reconsider their professionalism. 

One might use “not playing with a full deck” when making fun of a friend who is always fumbling their words, making mistakes, or missing out on bits of a conversation. It might also be used more cruelly to refer to someone that is only observed from a distance. It could certainly come across as abusive and bullying in the right scenario. 


Example Sentences With “Not playing with a full deck” 

  • After hearing his presentation I’m not sure he’s playing with a full deck. 
  • Did you hear what he said yesterday? We couldn’t stop laughing. I’m sure he’s not playing with a full deck.
  • Her jokes totally fell flat, she’s definitely not playing with a full deck.
  • My dad used to wonder if his friends were playing with full decks. I’m pretty sure he was onto something.
  • You better choose wisely here or we might wonder if you’re playing with a full deck. 


Why Do Writers Use “Not playing with a full deck?” 

Writers use “not playing with a full deck” in the same way and for the same reasons that it’s used in everyday conversations. It might be used when one character is considering the actions of another. Perhaps the secondary character did something outrageous or not particularly intelligent. This phrase could easily fit into the dialogue or a character’s thoughts. That being said, as with all idioms, euphemisms, aphorisms, and proverbs, it’s easy to misuse the phrase or include it in a section of dialogue where it doesn’t feel natural. Writers always have to be on the lookout to ensure that this doesn’t happen. 


Origins of “Not playing with a full deck”

“Not playing with a full deck” is common when it comes to these kinds of sayings, there is no clear source for its origin. It was likely used centuries ago in a different form before evolving to be what it is today. Although there is no clear evidence this is the case, it’s a popular belief that the origin of this phrase dates back to the 1500s when a tax was levied against decks of playing cards. In order to get around the tax, people would buy decks with 51 cards rather than the standard 52. Despite how interesting this is, it’s not considered to be the true origin.


Related Idioms 

  • “That ship has sailed.” 
  • “Through thick and thin.” 
  • Shape up or ship out.”  
  • Not firing on all cylinders”
  • “Two bricks shy of a load”
  • “Missing something upstairs”
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