SubjectLines

Email Spam Words to Avoid — The 175-Word List, Ranked

Spam word lists are the most-clipped and least-understood artifacts in email marketing. The honest version: filters in 2026 lean on domain reputation, authentication and engagement far more than vocabulary — but the words still matter at the margin, especially for new domains, cold outreach, and anyone whose engagement metrics are already soft. This is the working list this site's checker and tester score against, split the only way that's useful: words with no legitimate subject-line use (high-risk), and ordinary commerce words that turn risky when stacked (medium-risk).

Quick answer: Avoid outright: '100% free', 'act now', 'risk-free', 'winner', 'make money', 'guaranteed' — the 107 high-risk words (−8 each in our scoring). Use sparingly: 'offer', 'discount', 'reminder', 'last chance' — the 68 medium-risk words (−3 each, risky stacked). And remember: reputation and engagement outweigh vocabulary.

High-risk words: never in a subject line

These 107 words and phrases are classic filter bait with essentially no legitimate subject-line use. Each costs −8 in our tester's scoring (capped at −24 per line):

  • Money and income bait: 'make money', 'earn $', 'cash bonus', 'double your income', 'financial freedom', 'work from home', 'no credit check', 'pre-approved', 'get out of debt'.
  • Fake urgency and hype: 'act now', 'limited time', 'offer expires', 'while supplies last', 'urgent', 'hurry up', 'this is not spam'.
  • Free-and-guarantee clusters: '100% free', 'free gift', 'no obligation', 'no strings attached', 'guarantee', 'satisfaction guaranteed', 'risk-free', 'zero risk'.
  • Prize and lottery framing: 'winner', 'you're a winner', 'lottery winner', 'claim your prize', 'you have been selected', 'congratulations'.
  • Health and pharma spam canon: 'weight loss', 'miracle diet', 'viagra', 'reverse aging', 'removes wrinkles', 'online pharmacy', 'lose weight'.

Medium-risk words: fine alone, risky stacked

These 68 words are ordinary commerce vocabulary — a single 'sale' or 'invitation' in a wanted email delivers fine. The scoring docks −3 each (capped at −9) because stacking them is how wanted email starts reading as promo:

  • Offer family: 'offer', 'discount', 'deal', 'coupon', 'promo code', 'voucher', 'flash sale', 'clearance', 'bargain'.
  • Time pressure, soft: 'last chance', 'ends today', 'today only', 'final notice', 'last call', 'limited', 'hurry'.
  • Commerce mechanics: 'order now', 'shop now', 'buy one get one', 'free shipping', 'redeem', 'signup bonus', 'stock up', 'trial'.
  • Business patter: 'reminder', 'membership', 'consultation', 'commission', 'exclusive', 'insider', 'secret'.

Why 'free' isn't the death sentence it used to be

The word 'free' sits on the medium list, not the high one, for a reason: modern filters treat it as one signal among hundreds, and a wanted newsletter saying 'free template inside' to an engaged list delivers without drama. What actually predicts the junk folder, in order: domain reputation and authentication (SPF/DKIM/DMARC — Gmail and Microsoft made these mandatory for bulk senders in 2024), reader engagement (do your opens and replies look wanted?), list hygiene (spam-trap hits and complaint rates), and only then vocabulary. Words are the dress code, not the bouncer — but nobody meets the bouncer looking sloppy.

The stack test

The pattern that actually hurts is stacking: multiple medium-risk words plus shouting plus punctuation pressure. 'URGENT!!! 100% FREE miracle offer inside!!!' scores 26/100 — triple exclamation marks (−8), '100% free' (high, −8), 'miracle' (high, −8), 'offer' (medium, −3). Compare 'Your Q4 plan: 2 spots left this month' at 81: zero triggers, zero shouting, and the deadline is real ('this month') rather than performed ('act now'). Same information, opposite filter posture.

How to write around the list

Replace the mechanism, not just the word. 'Act now — limited time' becomes 'doors close Friday' (a real deadline beats performed urgency). '50% OFF!!!' becomes 'our twice-a-year sale is on' (specific beats shouted). 'FREE gift inside' becomes 'a small thank-you for you' (warmth sells without the trigger). Run every rewrite through the spam word checker — it flags severity per word and the tester shows the score moving as you clean up.

What SubjectLines doesn't do

  • Not a filter-bypass service — we clean vocabulary, not consent or reputation.
  • No promise of inbox placement; anyone guaranteeing '100% inbox delivery' is selling the thing this page warns about.

Frequently Asked Questions

What spam words should I avoid in email subject lines?
The 107 high-risk words: '100% free', 'act now', 'risk-free', 'winner', 'make money', 'guarantee', 'no obligation', 'urgent', 'this is not spam', 'weight loss', 'viagra' and their kin — none has a legitimate subject-line use. The 68 medium-risk words ('offer', 'discount', 'reminder', 'last chance') are fine individually; stacking is what hurts.
Does the word 'free' send email to spam?
Not by itself in 2026. 'Free' is medium-risk: one instance in wanted email to an engaged list delivers fine. It combines badly — 'free free free', '100% free', ALL-CAPS 'FREE' — and with already-weak engagement signals. Score it −3, not −8.
Do spam words still matter in 2026?
Yes, but as a minor factor. Gmail's and Microsoft's 2024 bulk-sender rules made authentication and engagement dominant; AI filters also read tone (ALL-CAPS shouting remains a reliable negative signal). Clean vocabulary is necessary hygiene and insufficient armor — reputation does the heavy lifting.
How do I check my email for spam words?
Paste the subject line (and ideally the preheader) into the spam word checker — it scans 175 trigger words, ranks each hit high/medium, and suggests calmer replacements. For full emails, most ESPs run content checks at send time; treat the subject line as the highest-leverage surface to clean.
Why did my email go to spam if there are no spam words?
Almost always one of: no SPF/DKIM/DMARC (or misconfigured), a low-quality list with spam traps or dead addresses, a volume spike from a new domain, or sustained low engagement teaching the filter your mail isn't wanted. Words were never the constraint — reputation is.

More tools used in this guide

Spam Word Checker

Scan your subject line against 175 spam trigger words — high-risk and medium-risk flagged, with fixes.

Subject Line Tester

Paste a subject line — get a 0–100 score, client truncation previews, and the exact fixes that raise it.

Inbox Preview Tool

Subject + preheader rendered as Gmail desktop, Gmail mobile and Outlook will show them — before you send.

More guides

How to Write Email Subject Lines

The seven-step process for writing subject lines that get opened — draft, check, trim, preview — with the ten checks that matter in 2026.

Email Subject Line Examples

A working library of scored subject line examples by scenario — welcome, promo, event, re-engagement, announcement — with the check each one passes.