Deliverability

Spam words, and what modern filters really look at

Published 21 August 2026 · 5 min read · By Ripe Leads

The short answer

Individual spam trigger words matter far less than people think. Modern filters weigh sender reputation, engagement and behaviour far more than any word list. A trusted sender can write free and still reach the inbox; an untrusted one gets filtered whatever they write. Fix reputation and relevance, not your vocabulary.

The spam-word checklist is one of the most durable myths in cold email. It survives because it is easy to act on, and it persists despite the fact that filters stopped working that way years ago.

The word-list myth

The belief is that certain words, free, guarantee, offer, act now, trip the filter, so you avoid them. There was a grain of truth to this a long time ago, and almost none now.

Modern filters do not scan for naughty words in isolation. They judge the sender and the pattern. A reputable sender can use free in a sentence and land in the inbox; a burned domain gets filtered writing nothing but plain prose.

What filters actually weigh

The signals that decide inbox placement are mostly about you, not your wording.

Sender reputation, the domain and IP history, covered in reputation and blacklists.
Engagement, whether recipients open, reply, or mark as spam.
Authentication, SPF, DKIM and DMARC set up correctly.
Sending behaviour, steady volume, low bounces, no sudden spikes.

Where wording still matters, a little

Content is not entirely irrelevant. A message that reads like textbook spam, all caps, lots of links, hard-sell hype, aligns with what filters expect from bad senders and adds to a picture reputation already paints. But it is a minor input, not the main event, and cleaning up genuinely spammy writing is really about sounding human.

RepReputation and engagement decide inbox placement far more than any word. A trusted sender can write free; an untrusted one cannot write anything into the inbox.

The habits that actually keep you inboxed

None of them are about vocabulary.

Verify your list so bounces stay low.
Warm new domains and keep volume steady.
Send relevant mail people want, so complaints stay near zero.
Set up authentication properly and remove opt-outs at once.

Stop editing words, fix the system

Time spent hunting for trigger words is time not spent on the things that decide delivery: the list, the reputation, the relevance. Write like a human, keep the technical setup clean, and the occasional ordinary word will not hurt you. If you are in spam, the cause is almost always upstream of your wording, in deliverability fundamentals.

Frequently asked

Do spam trigger words still matter in cold email?

Much less than people think. Modern spam filters weigh sender reputation, engagement and sending behaviour far more heavily than any individual word. A trusted sender can use words like free and still reach the inbox, while an untrusted domain gets filtered regardless of wording. Fixing reputation and relevance matters far more than editing vocabulary.

What do modern spam filters actually look at?

Mainly the sender: domain and IP reputation, how recipients engage, whether authentication such as SPF, DKIM and DMARC is set up correctly, and sending behaviour like steady volume and low bounce rates. Content plays a minor role, and only when an email reads like textbook spam. Inbox placement is decided by who is sending and how, not by a word list.

How do I stop my cold emails going to spam?

Focus on the fundamentals rather than wording: verify your list to keep bounces low, warm new domains and keep volume steady, send relevant mail people actually want so complaints stay near zero, set up authentication properly, and honour opt-outs immediately. If you are landing in spam, the cause is almost always reputation or targeting, not the words you used.

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