Top 10 Words to Avoid in Email Subject Lines

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There are certain words you don’t, can’t, shouldn’t, and mustn’t use within your email subject line if you want to pique people’s interest while avoiding spam blockers. It’s one thing if you’re sending a personal email to a prospect or customer, but if you’re sending mass emails, you’re not going to get very far if 90% of your messages get blocked before they ever reach their intended recipient.

There are so many spam trigger words, we could write a nice thick book about them. In fact, has a list of 455 spam trigger words to avoid. And this is on top of the words that set off people’s own mental defenses — emails that promise untold riches and exclusive rewards reserved only for a special elite few. Remember that prince from Nigeria?

Ten Words to Avoid

As with anything in life (except for maybe poker) you want to be open and honest with people. Be direct, be humble, avoid bragging and boasting, and avoid words and phrases like the ones below so you can actually get your message in front of the people you want to reach.

  • Anything to do with money. Free, profits, price, credit, and anything with a dollar sign. You not only look sleazy, but the spam filters are sure to pick these up, and they’ll never reach their destination.
  • Marketing. Email marketing may be one of the most successful marketing channels out there, but that doesn’t mean email service providers want you clogging up their servers with it. Additional terms like email marketing, direct marketing, digital marketing, and account-based marketing (our favorite) are just a few other examples. You may be doing marketing when you email clients, but that doesn’t mean you need to remind them you’re doing it.
  • Exclusive. Surprisingly, the synonyms for this word aren’t on’s list, but this one is. It’s almost as if it’s. . . the only one of its kind (ba-dum-tss). If you have a ‘special offer’ only for a select group of people, use any of the other words to tell people about it, but don’t use this one.
  • Superlatives. Leave the hard-sell advertising copy to Madison Avenue. Words like FANTASTIC, INCREDIBLE, and AMAZING smack of desperation and make you look fly-by-night. Let your product and your offer do the talking. Your prospects will figure out if you’re fantastic and amazing without you bragging about it.
  • Days of the week. This is especially true because of the flood of emails for things like Cyber Monday, Black Friday, Giving Tuesday, and so on. In fact, there are significant drops in open rates of emails with day names in the subject line. Words like “today” are also suspect, but in those cases, it’s usually around phrases like “do it today” and “order today.”
  • Emojis. Emojis and symbols are major spam triggers. Also, you’re not 16.  😎
  • Be your own boss. The mating cry of multi-level marketers and get-rich-quick hucksters. If people want to be their own boss, they already are. And if they’re not, that phrase is not going to make them decide to quit their job and go into business for themselves. Nothing says “could be a scam, could be worse,” than this phrase.
  • Anything to do with sex. It’s not that we’re prudes, it’s that anything related to sex at all is immediately shut down by almost every email server in the world. It doesn’t matter if you’re actually selling those products or that your prospects absolutely want to hear from you. Sex may sell, but not when it’s used in your subject line.
  • Earn. Again, anything that has to do with money, like earning extra income or earning cash, will not only drop the spam hammer, but people are too well-conditioned to believe its promises.
  • Free. This — and “bonus” — may be one of those words that make some people take notice, but many more see it as open-bait.

Make Email Marketing Work For You

To start, try to avoid sending generic messages to everyone in your database. I know it can be difficult, especially with limited resources and pressing deadlines, but segmenting your audience, personalizing your messaging and testing frequency can lead to improved open and click-through rates.

At EverString, we tailor our messaging based on the FIRE methodology. We segment prospects that are not only a good fit for our offering, but they’ve recently shown purchase intent on keywords that we care about. Now it’s up to us to create relevant and timely offers that will create engagement. A good way to identify companies that are a good fit for your product is to work with your sales and marketing teams to develop an Ideal Customer Profile (ICP).

Related Video: How to Write Strong Subject Lines for Prospecting

Hopefully, once you start building an email relationship with your prospects, your messages will make it to their inbox. But when you’re starting out with those initial conversations, don’t risk anything. Avoid the “naughty words” and keep on your prospects’ — and their email servers’ — good side.

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