Why you should use synonyms and related keywords

Search engines have become significantly more intelligent than they were in the past. You no longer need to repeat the same keyword a dozen times to be noticed. Google’s AI models, as well as large language models like ChatGPT and Gemini, now understand meaning, intent, and context. So, does that mean you don’t need to use synonyms and related keywords? Of course not, and to avoid any confusion, you should definitely. Using synonyms and related keywords isn’t just about improving your writing style. It also helps both people and search engines interpret what your page is about.

What are synonyms and related keyphrases?

A synonym is a word that shares the same or a very similar meaning as another. For example, “fast” and “quick” are synonyms.

A related keyphrase, on the other hand, isn’t necessarily a direct synonym; it’s a word or phrase connected to the same topic. If your main keyphrase is chocolate candy, then sweets, dessert, or sugary treats could all be related keyphrases.

When you use synonyms and related keywords, you make your writing more natural to read and more informative. You also help search engines understand your topic in greater depth, which improves your chances of appearing in relevant searches.

Why variation matters for SEO and readability

Modern SEO copywriting and readability are all about helping people and search engines understand the context of your writing. When you vary your word choice and use synonyms and related keywords, you make your text more engaging for readers and clearer for algorithms.

If you’ve ever read a page that repeats the same keyword endlessly, you know how mechanical it feels. Years ago, that might have worked. Today, it can frustrate readers and even harm your SEO.

Using synonyms and related keywords also improves your readability score, a ranking factor that reflects how easy your text is to follow. When your content is varied, visitors stay longer, bounce less, and gain a better understanding of you.

How search engines and AI understand language today

Search engines rely on natural language processing (NLP) and machine learning to interpret meaning. Instead of simply counting keywords, they analyze how words relate to each other in context.

That’s why a post about AI copywriting tools can appear in searches for AI content writing software. Google understands those terms belong to the same topic. This is part of semantic SEO, which involves optimizing content so that search engines can grasp its overall context rather than just individual words.

By naturally incorporating synonyms and related keywords, you help Google recognize that your content addresses a broader range of questions related to your topic.

Understanding search intent is crucial here. Once you know what users expect to find, you can use language that naturally fits their intent while still covering your main keyphrases.

Keyword density versus natural language

In early SEO, keyword density, or the percentage of times a keyword appeared in your text, was seen as a signal of relevance. But search engines have outgrown that. Today, keyword density has little to no impact on search engine rankings.

Still, using your synonyms and related keywords naturally throughout your text can help clarify context. The key is balance: write as if you’re explaining the topic to a colleague or client.

Yoast SEO’s readability and SEO guidelines highlight why tone, pacing, and sentence length are now essential parts of optimization. The goal isn’t to count words, it’s to communicate clearly.

If you remember the candy shop analogy from before, let’s look at a real-world example. If you type in ‘best candy store New York’ on Google, the results will show pages about ‘candy stores’ and ‘candy shops’. Google understands that ‘store’ and ‘shop’ are synonyms and treats them as such. 

This doesn’t detract from the fact that you should still incorporate your focus keyword a few times throughout your post. After all, the focus keyword is still the word or phrase your audience was searching for. These are the words your audience uses and will expect to find in your text. That exact match remains important. However, to avoid using your keyword too many times, also known as keyword stuffing, you can use synonyms and related keywords to achieve a more natural flow of language. That way, you can rank on these keywords while keeping your text attractive and readable.

Find related keyphrases using our Semrush integration

Yoast SEO can help you find related keyphrases based on your focus keyword, saving you time and hassle. All you need to do is click the button to ‘Get related keyphrases’; you’ll find it right underneath your focus keyword in the Yoast SEO sidebar. You’ll see a list of related keywords and search trend data when you click that button.

As a Yoast SEO Premium or Yoast SEO for Shopify user, you can add up to five related keyphrases to your SEO analysis. This lets you optimize your text for these additional terms similarly to your focus keyphrase. As always, you’ll see our familiar feedback bullets to guide you. If you’re a Yoast SEO Free user, you can explore related keyphrases using the tool, but you won’t be able to add these to your SEO analysis.

Yoast SEO can help you balance the use of your keywords, synonyms, and related keywords by recognizing word forms in different languages. If you want to know more, you can read about the related keywords feature in Yoast SEO for WordPress and the related keywords featured in Yoast SEO for Shopify.

How often should you use synonyms and related keywords?

The use of synonyms versus the use of focus keywords is not an exact science. The most important criterion is the way readers will experience your text. So, read and re-read it. Is it engaging and easy to read? Or are you getting annoyed by the constant use of a certain term? Be critical of your writing and ask others for feedback on your text. 

As mentioned earlier, you can add your related keywords to the analysis in Yoast SEO Premium and Yoast SEO for Shopify. By adding these, the plugin can check whether you’re using them in your text. Your focus keyword remains the most important keyword, though, and that’s why the plugin is less strict in its analysis of your related keyphrases.

You’ll also be able to add synonyms of your focus and related keywords when you use our Premium SEO analysis or Yoast SEO for Shopify. These analyses include checks to ensure you’ve used these synonyms in your text and your meta description, introduction, subheadings, or image alt text. Moreover, our keyphrase distribution check will reward you for alternately using your keyphrase and its synonyms throughout your text.

Make those related keyphrases and synonyms work for you

As we mentioned earlier, Google has come a long way since its early days in the field of SEO. It can understand texts, consider related concepts and synonyms, and recognize related entities. This enables it to serve its users with the best results. And part of being the best result is ensuring your texts are easy to read. Google wants to serve readable texts.

So make sure you deliver! Consider synonyms for your keyword or keyphrase and utilize them to your advantage. Take a moment to come up with a few alternatives for your keyword. Additionally, consider topics closely related to your keyword. You’ll notice that writing a naturally flowing text becomes much easier when you don’t have to use your focus keyword in every other sentence. Using synonyms and related key phrases helps Google understand the context of your text, which increases your chances of ranking.

In conclusion

Using synonyms and related keywords isn’t about tricking algorithms. It’s about writing naturally for humans while helping machines interpret meaning. When you vary your word choice, your writing becomes clearer, richer, and more engaging. That’s what today’s search engines reward: real content that genuinely helps users and shows topical depth.

Read more: Does readability rank? On ease of reading and SEO »

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