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Email spam words: Five tips to avoid the spam folder and email writing best practices

Email marketing is a valuable direct marketing tactic for driving revenue and a great supplement to any online marketing strategy. It’s so popular, in fact, that getting your business emails delivered, opened and read isn’t always easy.

One of the biggest barriers to reaching your audience’s inboxes are spam filters. Certain email words are likely to trigger spam filters, so it’s important to follow best practices to keep your business emails out of the spam folder and increase their overall effectiveness.

In this article, we’ll share common email spam trigger words to avoid, rules to follow to ensure your emails get delivered correctly and business email writing best practices.


Table of contents


Email spam words not to use

Below is a list of English words to avoid when writing emails so they don’t get marked as spam. Some are more obviously “spammy” than others, but all of these email phrases, used incorrectly or aggressively, can land your email in spam folders.

For example, “Free gift” or “Special promotion” could be fine when sent to segmented groups of long term customers to celebrate a holiday or promote a sale. If you write “FREE GIFT!!!” in all caps accompanied by several emojis and send it to your entire mailing list, that could seem fishy and a spam filter may catch it. Keep context and style in mind when reading through this list:

Too good to be true

  • “Free money”

  • “Pure profit”

  • “Risk free”

  • “No obligation”

  • “Free gift”

Urgent, bossy, or attempts to spark intrigue

  • “Limited time”

  • “Expires”

  • “Act now”

  • “Click below”

  • “Instant access”

  • “Don't delete”

Exaggerations or superlatives

  • “Fantastic deal”

  • “Special promotion”

  • “Lowest price”

  • “Best rates”

  • “Best price”

Large or important purchase or credit related words

  • “Mortgage rates”

  • “Refinance”

  • “Lower interest rates”

  • “Life insurance”

  • “Unsecured credit”

  • “Credit card”

Attempts to be personal or make you feel special

  • “Dear friend”

  • “Sir or madam”

  • “You've been selected”

Health, pharmaceutical, or weight loss related

  • “Weight loss”

  • “All natural”

  • Brand names of any kind other than your own

Job opportunity or side gig related

  • “Join millions”

  • “Multi-level marketing”

  • “Increase sales”

  • “Own boss”

  • “Financial freedom”

  • “Extra income”

  • “Extra cash”

  • “No hidden costs”

  • “No hidden charges”

Unprofessional or offensive words or phrases

Some of these may not seem like a big deal in a real-life conversation with your friends or maybe even your co-workers. However, many slang terms or improper labeling perpetuate stigmas against the disability community that can appear ableist or are simply dehumanizing.

  • Anything related to mental health or mental illness: “crazy”, “psycho”, “OCD”, “insane”

  • Slang or colloquial terms: “my bad”, “no biggie”, “chill”, “sick”, “sucks/sucked”

  • Racial slurs

  • Swear words

It’s also important to note that any mentions of social security numbers can signal “scam” to email service providers (ESPs) and should be avoided. Eccentric fonts or weird symbols will also affect email deliverability and open rates since spammers often use them.

Even if you think you’ve avoided all offensive words, slang terms and followed stylistic best practices, you should still test your email campaign to make sure it goes through before sending. Testing is especially important if it’s a bulk email, weekly newsletter or large cold email campaign as tons of email bounces at once or low engagement can affect your email health and cause email delivery problems.


5 ways to not end up in the spam folder

Words aren’t the only thing that can get your emails marked as spam. Certain rules, established by the CAN-SPAM Act or Europe’s GDPR laws to protect commercial email recipients, need to be followed as well.

1. Include unsubscribe links

Senders must include a clear and conspicuous explanation of how to not receive future emails.

2. Match your email subject line to the contents of your email

Message matching is a copywriting 101 principle, but the CAN-SPAM Act also states that the subject line “must accurately reflect the content of the message”.

3. Include your physical address on your emails

If you’re a service based business (no physical location), consider getting a virtual mailbox.

4. Send an HTML and text version

HTML-only emails can trigger spam filters, since spammers are often too lazy to bother with a text version. Additionally, image-heavy emails won’t load in areas with minimal WiFi and the text version is what’s used on devices like smartwatches.

5. Use double opt-in forms

Adding an extra step before people join your email list ensures the people on it really want to be there, increasing open rates and conversions. Opt-in forms also signal to email service providers that you’re serious about keeping a clean email list and practice good email list hygiene.


Business email writing best practices

Your business emails have passed the spam test. Now it’s time to get people engaging with them, clicking through and replying to them.

Professionalism in emails is important, but it’s possible to overdo the formality. There are words in the English language that you would probably never use in your daily speech. In addition to complex industry jargon, steer clear of words you’re using for the sake of sounding businesslike.

Structuring your business or professional emails

Organizing your business emails makes them more effective and can also help you tackle writer’s block. Follow this outline when structuring your emails.

  1. Greeting

  2. Friendly opening line that leverages personalization

  3. Reason for your email

  4. Instructions on where they can find further information or explain the purpose of any attachments

  5. Closing line

  6. Sign off

Here’s how this would look in practice. The example below is for an internal communication email, but this structure works for email marketing campaigns as well.

Hi [name],

I hope you had a great weekend!

I wanted to shoot you a quick note with a friendly reminder to sign up for company benefits by the end of next week.

Attached is a .pdf file outlining the different insurance plans available.

Please don’t hesitate to reach out with any questions.

Talk soon,

[Your name]


Keep it simple and clear but avoid over-explaining anything. Trust that if the person has any questions or clarification, especially if you noted your eagerness to help, that they’ll reply with them.

Tips for writing effective business emails

  • Use active not passive voice. This is key to strong writing in general, but especially in emails. If you’re sending an email giving bad news, softening the blow with passive language can be tempting, but effective email content gets to the point right away.

  • Avoid adverbs and fillers. Words like “really”, “very”, “completely” and “literally” weaken your writing. Opt for synonyms (e.g. “insightful” vs. “really interesting”) or power words (e.g. “tested”, “new”, “proud”) that evoke emotion or trigger action instead.

  • Include a call to action (CTA). If you need the recipient to take action or are trying to land new customers, make the next step clear. Include relevant deadlines or clear buttons on how to subscribe or buy a product, but don’t implement a false sense of urgency. Keep your calls to action (CTA) towards the end. If it’s a long email with a request towards the beginning, be sure to recap the action items you’d like from the recipient.

  • Ditch the boring signoff. An email signoff usually won’t make or break your email content, but it’s a great way to end things on a friendly note (especially if you’re dealing with delicate subject matter). Phrases like “best regards” or “best wishes” are often overdone, so opt for something with a little more originality.


Final thoughts

Rules change, spam filters get smarter, new words are added to the spam trigger list as new industries and products come about and the culture shifts. When in doubt, test your email campaigns and email words or ask someone to read over your email content before sending.

Staying away from spam words is an important first step of writing email marketing campaigns or business emails, but if you want your them to be effective, they need to be well-written too.

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