Understanding the Idiom: "have bats in one's belfry" - Meaning, Origins, and Usage

Idiom language: English
Etymology: 1899, from tendency of bats to fly around erratically, with “belfry” indicating “head, mind”.
  • insane

When it comes to idioms, there are many phrases that can be confusing for non-native speakers. One such phrase is “have bats in one’s belfry”. This idiom is often used to describe someone who is acting strange or irrational. However, understanding the origin and meaning behind this phrase can help shed light on its usage.

By gaining a better understanding of this idiom, readers will be able to use it more effectively in their own conversations and writing. Additionally, they will have a greater appreciation for the rich history and cultural significance of idiomatic expressions like “have bats in one’s belfry”.

Origins and Historical Context of the Idiom “have bats in one’s belfry”

The idiom “have bats in one’s belfry” is a colorful expression that refers to someone who is perceived as crazy or eccentric. The phrase has been around for quite some time, but its origins are not entirely clear. However, there are several theories about where this idiom came from.

One theory suggests that the phrase originated from the practice of keeping live bats in church bell towers during medieval times. Bats were believed to be able to ward off evil spirits, so they were often kept in belfries as a form of protection. Over time, people began associating the strange noises made by these creatures with madness or insanity.

Another theory suggests that the phrase may have come from an old English word “batt,” which meant “to strike.” In this context, having bats in one’s belfry could mean having something constantly striking against your head, causing you to act erratically.

Regardless of its origin, the idiom “have bats in one’s belfry” has become a common expression used today to describe someone who appears irrational or out of touch with reality.

In terms of historical context, it is worth noting that mental illness was not always well understood or treated with compassion throughout history. People who exhibited symptoms such as hallucinations or delusions were often viewed as possessed by demons or punished for their supposed sins. It wasn’t until much later that mental health care became more humane and effective.

Usage and Variations of the Idiom “have bats in one’s belfry”

When it comes to idioms, there are often variations and different ways to use them. The idiom “have bats in one’s belfry” is no exception. This phrase is used to describe someone who behaves in a strange or irrational manner. However, there are various ways this idiom can be altered or expanded upon depending on the context.

One common variation of this idiom is “have bats in the attic.” This version still refers to someone acting strangely but implies that they have strange thoughts or ideas rather than just behavior. Another variation is “have bats in the cave,” which has a similar connotation as the previous example but with a more crude tone.

In addition to these variations, this idiom can also be used as part of longer phrases such as “not all there” or “a few screws loose.” These phrases expand upon the idea that someone may not be entirely rational and add additional emphasis to their erratic behavior.

Synonyms, Antonyms, and Cultural Insights for the Idiom “have bats in one’s belfry”


  • Off one’s rocker
  • Not playing with a full deck
  • A few sandwiches short of a picnic
  • Crazy as a loon
  • Batshit crazy (related to our idiom)

These expressions are all used colloquially to describe someone who is behaving erratically or irrationally. While they may not have the same origin as “have bats in one’s belfry,” they convey similar meanings.


  • Sane
  • Rational
  • Level-headed
  • Stable-minded
  • In control of one’s faculties/li>

These words represent the opposite end of the spectrum from our idiom. They describe individuals who possess sound judgment and emotional stability.

Cultural Insights:

The phrase “bats in one’s belfry” comes from an old superstition that bats were associated with darkness and evil spirits. Bats are often depicted as nocturnal creatures that fly around at night, which can be unsettling for some people. Bell towers were also believed to be haunted places where ghosts would reside.

Interestingly, many cultures have their own unique associations with bats. In China, for example, they are considered symbols of good luck and happiness. In Western culture, however, they tend to carry negative connotations.

Practical Exercises for the Idiom “have bats in one’s belfry”

If you want to improve your English language skills, it is important to not only understand idioms but also be able to use them correctly. The idiom “have bats in one’s belfry” may seem confusing at first, but with practice, you can easily incorporate it into your vocabulary.

Here are some practical exercises that will help you master the usage of this idiom:

  • Create a dialogue between two people where one person accuses the other of having bats in their belfry. Use this idiom appropriately and make sure the conversation flows naturally.
  • Write a short story or paragraph using the idiom “have bats in one’s belfry”. Make sure to provide context and use the idiom correctly.
  • Watch a movie or TV show that uses this idiom. Take note of how it is used and try to identify its meaning from context clues.
  • Practice using this idiom in everyday conversations with friends or family members. This will help you become more comfortable with using idiomatic expressions.

By incorporating these exercises into your daily routine, you will become more confident in using the idiom “have bats in one’s belfry” correctly. Remember, practice makes perfect!

Common Mistakes to Avoid When Using the Idiom “have bats in one’s belfry”

Avoiding Literal Interpretations

The first mistake to avoid when using this idiom is taking it too literally. The phrase “have bats in one’s belfry” does not mean that someone actually has bats living in their bell tower. Rather, it is a figurative expression used to describe someone who is crazy or eccentric.

Using Incorrect Pronouns

Another common mistake is using incorrect pronouns when referring to the person with “bats in their belfry”. The correct pronoun to use is “he” or “she”, depending on the gender of the person being described. It may be tempting to use “it” because of the word “bats”, but this would be grammatically incorrect.


  1. Douglas Harper (2001–2024), “batty”, in Online Etymology Dictionary.
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