---
title: "Split Infinitive | Intro to English Grammar"
description: "Split infinitive is an infinitive with a word, usually an adverb, between to and the verb. In Intro to English Grammar, it sits inside grammar debates."
canonical: "https://fiveable.me/fundamentals-of-the-grammar-of-standard-english/key-terms/split-infinitive"
type: "key-term"
subject: "Intro to English Grammar"
unit: "Unit 1"
---

# Split Infinitive | Intro to English Grammar

## Definition

A split infinitive is an infinitive with a word, often an adverb, placed between to and the verb, like "to boldly go." In Intro to English Grammar, it shows the difference between prescriptive and descriptive grammar.

## What It Is

A split infinitive is an infinitive in which another word comes between to and the verb, usually an adverb. So instead of "to go," you get "to boldly go" or "to carefully explain." In Intro to English Grammar, that construction matters because it shows how English grammar can be described in more than one way.

The term itself comes from the idea that the infinitive marker to and the base verb are being separated. Traditional grammar books often treated that separation as a mistake, especially in formal writing. That view is part of prescriptive grammar, which tries to tell you how language should be used according to a rule system.

Descriptive grammar looks at actual usage instead. From that perspective, split infinitives are not broken English at all. They are a normal English pattern that speakers use when the adverb sounds better before the verb than after it.

That placement can change rhythm or clarity. Compare "to explain clearly" with "to clearly explain." Both are grammatical in modern English, but the second version sometimes sounds smoother, more direct, or less ambiguous depending on the sentence. English often lets you move adverbs around for style, so the split infinitive is really about word order, not about a sentence falling apart.

This term shows up a lot in grammar classes because it sits right at the boundary between rule-based correction and actual language use. If you see a teacher mark one on a paper, the question is usually not whether the sentence is understandable. The question is whether the sentence matches a formal style preference, a descriptive analysis, or a specific editing convention.

## Why It Matters

Split infinitive matters because it is one of the clearest examples of the prescriptive versus descriptive split in English grammar. A lot of grammar rules students learn are not purely structural rules, they are style rules that came from older traditions of correctness. This term helps you see that distinction instead of treating every grammar warning as the same kind of rule.

It also gives you a useful tool for sentence analysis. When you notice "to" plus an adverb plus a base verb, you can ask a few sharper questions: Is the phrase clear? Does the adverb sound natural there? Is the sentence being judged for formal style, or just for whether it works as English?

That matters in editing too. In a lab report, essay, or short response, you may choose a split infinitive if it creates a cleaner sentence. In a more traditional style environment, you may revise around it if your instructor wants a formal tone. The term teaches you how grammar and style overlap, but do not always mean the same thing.

## Connections

### infinitive

A split infinitive only makes sense if you know what an infinitive is first. In English, infinitives usually look like "to" plus the base verb, such as "to write" or "to revise." The split happens when another word enters that space, so the base structure of the infinitive is the starting point.

### prescriptive grammar

Prescriptive grammar is where the "don’t split the infinitive" rule comes from. This approach treats some patterns as more correct or more formal than others, even if people use both in real life. Split infinitives are a classic example of a usage choice that prescriptivists may discourage.

### descriptive grammar

Descriptive grammar explains why split infinitives are acceptable in many modern analyses. Instead of judging the sentence first, it asks how speakers actually use English. From that angle, a split infinitive is just one normal way English word order can work for clarity or emphasis.

### [Grammaticality vs. Acceptability](/fundamentals-of-the-grammar-of-standard-english/key-terms/grammaticality-vs-acceptability)

This pair helps explain why split infinitives confuse people. A sentence can be perfectly acceptable to native speakers and still get marked down in a formal style tradition. The split infinitive is a good example of something that may be acceptable in everyday English even when a rule book discourages it.

## On the AP Exam

A quiz question may ask you to identify a split infinitive in a sentence, explain why it counts, or compare a prescriptive correction with a descriptive analysis. You might also be asked to revise a sentence for tone and decide whether keeping the split infinitive improves clarity.

When you answer, name the structure directly: "to" plus an inserted word plus the verb. If the prompt is about grammar theory, connect the example to prescriptive grammar or descriptive grammar instead of treating it like a simple typo. If the prompt is about editing, explain whether the split creates a clearer rhythm, or whether a version without it sounds more formal. The useful move is to show that you can spot the structure and explain the language choice, not just label it as right or wrong.

## split infinitive vs infinitive

An infinitive is the basic verb form with to, like "to run" or "to study." A split infinitive is a specific type of infinitive where another word comes between to and the verb, like "to quickly run." So every split infinitive contains an infinitive, but not every infinitive is split.

## Key Takeaways

- A split infinitive is an infinitive with a word inserted between to and the verb.
- The most common splitters are adverbs, especially when they make the sentence clearer or smoother.
- Traditional grammar often discourages split infinitives, but modern descriptive grammar accepts them as normal English.
- The phrase "to boldly go" is a famous split infinitive because the adverb sits between to and go.
- In English grammar class, this term is useful for comparing style rules with actual language use.

## FAQs

### What is split infinitive in Intro to English Grammar?

A split infinitive is an infinitive with another word, usually an adverb, placed between to and the verb. In grammar class, it is a common example of a form that older prescriptive rules often discouraged but modern usage often accepts.

### Is a split infinitive wrong?

Not in modern English usage. Descriptive grammar treats it as a normal construction, and many sentences sound clearer with one than without one. In some formal editing situations, though, a teacher or style guide may still prefer a revised version.

### What is an example of a split infinitive?

"To boldly go" is the famous example. The adverb boldly sits between to and go, which makes it a split infinitive. You can also make everyday examples like "to clearly explain" or "to carefully compare."

### Why do grammar books care about split infinitives?

They are a classic case of prescriptive grammar versus descriptive grammar. Some books treat them as awkward or informal, while modern analysis points out that English speakers use them naturally. That makes them a useful topic for discussing language rules, style, and meaning.

## Related Study Guides

- [1.3 Prescriptive vs. descriptive approaches to grammar](/fundamentals-of-the-grammar-of-standard-english/unit-1/prescriptive-vs-descriptive-approaches-grammar/study-guide/ZLaLCPNmMSERmIP3)

## About This Document

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