an infinitive with an adverb between `to' and the verb (e.g., `to boldly go')
a grammatical construction in the English language produced by inserting an adverb or adverbial phrase between to and a verb in its infinitive form
an infitive with another word, usually an adverb
a phrase in which to is separated from the verb
In the present tense, a verb phrase consisting of to followed by the base form of the verb ( to write). A split infinitive occurs when one or more words separate to and the verb ( to boldly go).
Syntactical construction in which an adverbial modifier comes between to and the infinitive. As the definition implies, "the term is actually a misnomer, as to is only an appurtenance of the infinitive" (M-W). It's perfectly okay to split infinitives--except that many people will think you're making an ignorant mistake. Do so at your own risk.
A split infinitive or cleft infinitive is an English-language grammatical construction in which a word or phrase, usually an adverb or adverbial phrase, occurs between the marker to and the bare infinitive (uninflected) form of a verb. One of the most famous split infinitives occurs in the opening sequence of the Star Trek television series: "to boldly go where no man has gone before." Here, the adverb "boldly" splits the full infinitive "to go."