What’s a Split Infinitive? Definition + When to Avoid It

Split infinitives happen when you place a word, usually an adverb (such as “softly” or “loudly”) between “to” and a verb (such as “sing”). 

They’re the topic of heated debates among writers, editors, and grammarians. Some argue split infinitives are a faux pas you should avoid at all costs. Others consider them a harmless construction that reflects natural speech and adds clarity and emphasis to writing.

My career as an editor has taught me the truth is somewhere in the middle. I’ve fixed split infinitives as often as I’ve explained to writers why splitting infinitives is sometimes okay.

In this guide, I break down what split infinitives are, when you should and shouldn’t use them in your writing, and how to fix them.

Defining infinitives and split infinitives

To understand what split infinitives are, you first need to know what infinitives are.

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To split, or not to split?

Grammarians are split (no pun intended 😉) on whether to avoid splitting infinitives.

On one side are those who still follow traditional grammar rules, which discourage using split infinitives because they can sometimes make sentences harder to read. 

On the other side are modern linguists, who point out that split infinitives are common in everyday speech (especially in American English) and can actually make sentences clearer and more memorable. 

Even the authors of Merriam-Webster’s Dictionary of English Usage have weighed in, arguing that “split infinitive” is a misnomer since “to” isn’t technically part of the infinitive verb. 

With this in mind, let’s explore when you typically should and shouldn’t split infinitives in your writing.

When to avoid split infinitives

Here are a few scenarios where you might want to avoid the split:

1. You’re working with a style guide that forbids split infinitives

Certain academic environments and professional publications adhere to style guides like APA or Chicago, which traditionally discourage split infinitives. In these cases, it’s important not to break the rules.

2. You’re doing formal or academic writing

Avoiding split infinitives in these types of writing — e.g., legal documents, traditional literary analyses, academic papers, etc. — can help you maintain the serious, formal tone they demand.

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3. You need to prevent ambiguity

Sometimes, the placement of an adverb can make it unclear which action it’s modifying. 

Look at this example sentence: 

Did Gena take time to make this decision (option 1), or will she act on it sometime in the future (option 2)?

Either of these two rewrites would be clearer, depending on which action you want to modify:

4. Your sentence includes multiple adverbs

When a sentence has many adverbs, it’s better not to split the infinitive because it can make the sentence tough to read. Instead, put the adverbs before or after the infinitive.

For example:

How to fix split infinitives

Another way to fix split infinitives is to replace the adverb-verb pair in a split infinitive with a stronger verb. 

For example, you could swap “to quietly say” with “to whisper.” They mean the same thing, but one avoids splitting the infinitive.

Below is a chart of split infinitive examples and the strong verb constructions you can exchange them for:

When you can use split infinitives

Split infinitives sometimes offer the most effective way to convey your meaning or achieve a certain goal with your writing. You might use them when:

1. The adverb would be out of place if moved

Take this sentence as an example: 

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2. You want to highlight a certain action

Consider this example: 

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3. You’re aiming for stylistic effect

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4. You’re mirroring natural speech

Conclusion

Split infinitives can be tricky to wrap your head around, but with this guide, you have all the information you need to use them correctly in your writing. 

Remember that a split infinitive simply means an adverb or other word has been placed between “to” and a verb — and you don’t necessarily need to correct it. 

You might use a split infinitive to emphasize a particular action, reflect real-life speech, or add flair to your sentence. Conversely, you should avoid splitting infinitives in formal or academic writing, if moving the adverb would create ambiguity, or when your sentence includes multiple adverbs.

For more information on writing well, check out our articles on improving your vocabulary and writing concisely and effectively.

FAQs

What is the most famous split infinitive?

One of the most famous split infinitives is a phrase in the opening sequence of Star Trek: “To boldly go where no man has gone before.”

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Why are split infinitives bad?

Split infinitives aren’t inherently “bad.” People debate them because of traditional grammar rules, which encourage moving adverbs before “to” or after the verb to unsplit the infinitive. However, split infinitives are common in everyday speech and can even help make your sentences easier to understand and more impactful.