1. Acting on Impulse.

On the opposite spectrum of people who are cautious, judicious, and prudent, are those who are impulsive, rash, impetuous and imprudent.

Someone who is described as impulsive acts on impulse (instinct or a sudden desire to do something.) An impulsive person doesn't think about consequences before doing something. People who are impulsive often act on emotion and often make spur-of-the-moment decisions.

Rash means thoughtless or rushed, without consideration of consequences. If something is done in a rash manner, it usually implies haste, recklessness, and speed. For instance, "She made a rash decision to purchase the property, sight unseen."

Impetuous is very similar to impulsive and rash, and is also used to describe hasty actions or impulsive people. People described as impetuous often show a lot of enthusiasm and are driven by great energy when making impulsive decisions.

Finally, imprudent is a more formal way to say "unwise." An impulsive decision could prove to be imprudent in the long run. Use impetuous to describe a person's character. If someone is often impulsive and prone to action without consideration, you would say that person is impetuous. You can also use impulsive to describe a person's character, but impulsive is viewed as more negative than impetuous. Finally, use rash and imprudent to describe actions that were done in haste and without thinking of the consequences.

Let's review with some examples:

The company lost money, because the V.P. of marketing made a -- rash decision and didn't consult with us first. Why did you sign the contract before meeting with our attorneys? That was very -- imprudent of you. He never thinks before doing anything; he is so -- impulsive. That's Jack for you; he likes to jump right into things without much planning; he's quite -- impetuous.

2. Bold and Rude

Now, let’s take a look at a few words that describe people or behavior that can be both imprudent and shocking or offensive. These next words are: audacious, brash, and brazen..

Someone who is audacious is not afraid to take risks and therefore is not afraid of offending others. An audacious comment or statement is one that is bold and possibly offensive, but also shows guts. The noun form of audacious is audacity. For example, “She had the audacity (nerve) to take credit for my work.” In a non-negative sense, audacious can be used to simply mean “brave,” but you’ll mostly hear it used in the negative sense of “overly bold and offensive.”

Brash is synonymous with audacious in this negative context. Brash is used to describe a person or action that is overly assertive to the point of being offensive. Someone who is brash is generally overly confident and maybe even disrespectful. Audacious is closer to "bold" while brash is closer to "rude." Brash also refers to hasty or impulsive
behavior. When you say something rude, without thinking before speaking, this would be considered brash. On the other hand, an audacious comment could be one that was thought of ahead of time, and said to purposely shock or offend. One other notable difference is that audacious is used more often to describe behavior, while brash is used more to describe the manner of someone’s communication. For example: “It was audacious of her to barge into the CEO’s office knowing he was in the middle of a meeting. Her brash comments surprised everyone in the room.”

The word brazen is a combination of both audacious (bold) and brash (rude). Brazen usually describes a negative act or a person who is shameless and has no regard for
his or her rudeness or inappropriateness. In other words, someone who is brazen is not afraid to be rude or shocking. A person who is brazen is both audacious (overly bold) and brash (harsh and offensive). A brazen act would be knowingly rude and offensive. Brazen arrogance refers to being aware of your arrogance and using it boldly and rudely to offend people.

To recap:

If someone was particularly bold, and maybe even shocking, you would describe this person or her behavior as -- audacious.
If a person or comment was harsh and rude it could be described as -- brash.
When people are purposely rude and offensive, and make no apologies for their actions they are -- razen.

3. Rude and Disrespectful

Since we’re on the subject of being bold and rude, let’s look at some words that describe rude and disrespectful behavior. Impudent, insolent, impertinent and irreverent are four such words.

Impudent essentially means "rude," and is especially used tc describe a person or behavior that is rude or disrespectful toward someone older or worthy of respect. For example, a child who "mouths off" to his teacher would be considered impudent. Both the child and his behavior can be described as impudent.

Insolent is a very strong critique that is often used to describe children who are rude, disrespectful, and "mouthy." Insolent is a particularly harsh critique if you use it to describe an adult.

The word impertinent is also used to describe someone who is boldly rude and disrespectful, especially to those in a superior position, but it's a more formal word to use for this purpose. Remember that impertinent also means "irrelevant," not to be confused with irreverent, which also means disrespectful and is used to describe people or behavior disrespectful toward religion, tradition, or culture.

To recap: If someone was being extremely rude and disrespectful you could describe the person and the behavior as -- impudent. A child who is disrespectful toward an adult would best be described by the word -- insolent. An employee who is rude or disrespectful toward his boss could be said to be -- impertinent. And a tourist who didn't seem to have much respect or deference toward the traditions or culture of the country his was visiting would be best described as -- irreverent..