Common spam trigger words, phrases, and formatting habits to avoid

Modern spam filters look at hundreds of signals, including your sender reputation, authentication, engagement, HTML quality, and the language you use.

While no single word will send your email to spam, repeatedly using overly promotional language, excessive punctuation, or misleading formatting can increase your spam score.

Below are 100 commonly flagged words, phrases, and formatting habits that are worth avoiding or using sparingly.

Good to know: Context matters. A single phrase on this list won't automatically trigger spam filters, but combining several of them can increase risk.

Money & Financial Claims

Make money fast
Get rich quick
Earn extra cash
Financial freedom
Double your income
Increase your income
Risk-free investment
Million dollars
Guaranteed income
Lowest price

Urgency & Pressure

Act now
Limited time
Offer expires today
Don't miss out
Last chance
Ends tonight
Immediate action required
Time is running out
Hurry
Final notice

"Free" & Promotional Language

Free
100% free
Free gift
Free bonus
Free trial
Free consultation
No purchase necessary
Complimentary
Claim your reward
Exclusive offer

Guarantees & Unrealistic Claims

Guaranteed
No risk
Satisfaction guaranteed
Promise you
Proven results
Amazing results
Miracle
Life-changing
Once-in-a-lifetime
Incredible opportunity

Sales & Discounts

Buy now
Order now
Lowest prices
Biggest sale ever
Massive discount
Save big
Clearance
Everything must go
Best deal
Unbeatable offer

Health & Wellness Claims

Lose weight fast
Burn fat
Cure
Eliminate wrinkles
Reverse ageing
Instant relief
Detox
Miracle cure
Fast results
Scientifically proven

Clickbait Phrases

You won't believe...
Shocking
Secret revealed
This changes everything
What happens next...
The truth about...
Hidden trick
Discover the secret
Mind-blowing
Viral

Trust & Security Claims

Click here immediately
Verify your account
Confirm your identity
Winner
Congratulations!
You've been selected
Urgent notification
Important message
Account suspended
Final warning

Formatting Habits That Can Trigger Spam Filters

ALL CAPS SUBJECT LINES
Excessive CAPITALISATION
!!! (multiple exclamation marks)
??? (multiple question marks)
$$$ symbols throughout the email
Repeated emojis (🎉🎉🎉🎉)
Excessive coloured text
Large blocks of bold text
Very large font sizes
Invisible or white-on-white text

HTML & Content Issues

Image-only emails with little or no text
Very short emails containing only a link
Excessive hyperlinks
Multiple different URL shorteners
Poorly formatted HTML
Broken HTML code
Misleading subject lines
Misleading sender names
Excessive attachments
Repeated use of promotional language throughout the email

Best Practices Instead

Rather than worrying about avoiding a single "bad" word, focus on building emails that recipients genuinely want to receive.

A few simple habits can make a much bigger difference:

Write naturally, as though you're emailing one person.
Keep subject lines honest and relevant.
Avoid exaggerated claims or unnecessary urgency.
Use punctuation sparingly.
Balance images with meaningful text.
Include a clear unsubscribe link.
Authenticate your domain with SPF, DKIM, and DMARC.
Send to people who have genuinely opted in.
Regularly remove inactive subscribers.
Prioritise valuable, engaging content over sales-heavy messaging.

Remember

Spam filters have become much more sophisticated than simple keyword matching. They assess your overall sender reputation, email authentication, engagement rates, complaint rates, HTML quality, and many other signals.

The occasional use of words like "free" or "exclusive" isn't a problem on its own. The biggest improvements to deliverability come from sending relevant, permission-based emails that subscribers enjoy opening and reading.

For more information on optimising deliverability, please review our resource here.