10 Professional Synonyms for “Brain Fart”

Are you worried that “brain fart” might be unprofessional or even offensive?

Perhaps you’re trying to show that something slipped your mind or didn’t make sense, but you want to do it in a good way.

Well, you’re in luck!

This article will teach you what to say instead of “brain fart” to ensure you don’t offend anyone.

Is “Brain Fart” a Bad Word?

“Brain fart” is a bad word because it is immature. It’s not smart to include it in your emails because it doesn’t convey an appropriate tone.

Generally, it’s inappropriate at work. Also, it’s quite offensive, as people don’t like reading the more informal and casual language that comes with an immature phrase like “brain fart.”

It is slang and means you temporarily forgot something or that something has slipped your mind.

There are countless better ways to say it. That’s why we think it’s appropriate to explore some alternatives.

Check out this message sample to learn how to use it effectively:

I’m afraid I had a bit of a brain fart, mate. I have no idea what I’m supposed to be doing with this.


  • It’s informal and friendly.
  • It’s quite funny when you’re close to the person you’re talking to.


  • It can be very rude and offensive in the wrong setting.
  • It’s immature and unprofessional, so it’s never appropriate in an email.

It’s time to explore some alternatives because it’s clear that “brain fart” is an inappropriate phrase in formal writing. That’s where the remainder of this article comes in.

Read on to learn how to say “brain fart” professionally. We’ve provided some great synonyms to help you see what other options are available to you.

What to Say Instead of “Brain Fart”

  • Mental lapse
  • Got sidetracked
  • Mental block
  • Cognitive hiccup
  • Brief cognitive lapse
  • Momentary memory slip
  • Brief lapse in memory
  • Cognitive stumble
  • Lost my train of thought
  • Mind went blank

1. Mental Lapse

For a more appropriate way to say “brain fart” at work, you can use “mental lapse.”

It works really well because it keeps things formal and direct. It shows that you let something slip your mind, but you’re working on a way to fix the problems that came from it.

Generally, this works well when contacting your boss. It owns up to any mistake you might have made and implies that you don’t plan on making it again.

You can also refer to this email sample:

Dear Mr. Dane,

It was a mental lapse on my part.

However, I’ll do what I can to fix the situation, and we’ll be back on track soon.

All the best,
Milo Smart

2. Got Sidetracked

Feel free to use “got sidetracked” instead of “brain fart.”

It works well when emailing your teacher. You can use it to let them know you let something slip your mind.

It almost works as a sort of apology (provided you genuinely mean it). It’s a great way to own your mistake and show that you’re honest and accepting of any issues it might have caused.

Here’s a great example to show you more about how it works if you still need help:

Dear Ms. Burton,

I’m afraid I got sidetracked and lost track of what I was meant to do.

Can you please resend the information needed to complete this assignment?

Thank you so much,
Scott Barker

3. Mental Block

You might also benefit from using “mental block” as a professional way to say “brain fart.”

It removes the inappropriate nature of “brain fart” and simply yet formally shows you had a block in your brain and couldn’t remember something.

Try it when owning up to your boss. It lets them know that you made a mistake, but you’ll do what you can to avoid making the same mistake again.

You can also refer to this email sample:

Dear Miss Workman,

I’m afraid this was more of a mental block on my part.

I’ll fix the situation immediately to ensure something like this won’t happen again.

All the best,
Kyle Clarkson

4. Cognitive Hiccup

You can also use “cognitive hiccup” to sound a bit more friendly and conversational.

Of course, it still works well in professional emails, but it works best when emailing a coworker.

It shows that you value more friendly language when emailing people you work with. Also, it keeps things a bit more light-hearted, regardless of the mistake you made.

Also, check out the following example if you need help:

Dear Thomas,

We both made a cognitive hiccup here.

I’m not sure how we did it, but we should own up to the mistake!

George Frame

5. Brief Cognitive Lapse

You can try “brief cognitive lapse” as another way to say “brain fart.” Again, it removes the immaturity of the original phrase, making it a great choice to include in your emails.

Try using it when apologizing to a client. It shows that you take full responsibility for forgetting to do something.

Also, using the word “cognitive” helps the phrase to sound more genuine and professional. So, clients will usually prefer to receive an email with this language in it.

Here’s a great example to show you more about how to use it:

Dear Miss Austen,

It was a brief cognitive lapse on my part.

They don’t normally happen, but I do apologize that it occurred at this time.

Damian Scottsdale

6. Momentary Memory Slip

Next, it’s worth trying “momentary memory slip” when writing to your boss.

It’s a great way to own up to a mistake you made. Generally, your boss will be happy that you’ve been honest with them and explained how you might have forgotten to do something.

For the most part, it’s quite formal and respectful. That’s what makes it such a great choice in your writing.

If you’re still unsure, you can refer to this email sample:

Dear Mr. Taylor,

It was because I had a momentary memory slip that I overlooked that.

Please forgive my oversight, and I’ll do better next time.

Kind regards,
Max Bradshaw

7. Brief Lapse in Memory

For something slightly simpler, you can write “brief lapse in memory.”

Now, this is a great phrase that works in nearly every type of formal email. For instance, you can use it when emailing a boss, colleague, or client.

For the purposes of our example below, we think it’s worth mentioning how useful it is when writing to a coworker about a mistake you both made.

It’s a great way to be honest with each other and show that you both made similar mistakes in judgment or memory.

Also, you can refer to this email example:

Dear Tim,

I believe we both had a brief lapse in memory when working through this.

Perhaps we should think things through a little before we go again.

Jonathan Wells

8. Cognitive Stumble

You can use the fun and unique alternative that is “cognitive stumble” instead of “brain fart” as well.

This phrase works really well to spice up your emails, as it’s not something the recipient will likely have come across before.

You should try it when writing to a customer. It shows that you made a slight mistake when trying to help fix a problem for them, and you want to own up to it.

While it can be annoying for customers when you make mistakes, the sooner you own up to them, the better off you and your company will be.

Here’s a great example to help you if you are still confused:

Dear Miss Murphy,

I’m afraid that was the fault of my cognitive stumble.

It’s not likely to happen again! But you have my sincerest apologies.

George Foto

9. Lost My Train of Thought

It’s good to use a more idiomatic synonym in some cases, too. That’s where “lost my train of thought” comes in.

This is a common saying used by English speakers. It means you forgot where you were or what you were supposed to be doing.

We highly recommend it because it keeps things formal and friendly. So, it’s a great way to write an email to your professor.

It lets them know that you struggled or forgot about something when completing an assignment.

You may also review this sample email:

Dear Mr. Bryant,

I lost my train of thought while completing the task.

So, there were definitely a few things that I missed or forgot to do.

Best regards,
Dan Redmayne

10. Mind Went Blank

Finally, you can use “mind went blank” as a great saying instead of “brain fart.”

It removes the immaturity of the original phrase. It’s a formal and honest way to show that you’ve simply forgotten about something.

Generally, we recommend using this when emailing an employer. It’ll let them know that something slipped your mind, and that’s why you didn’t do a task for them.

Check out this email sample to help you understand it a bit better:

Dear Mr. Moore,

I’m afraid my mind went blank here.

I’m very sorry, and I won’t let something like that happen again.

Georgia Martins