infinitive : Idioms & Phrases
Infinitive mood
(Gram.) , that form of the verb which merely names the action, and performs the office of a verbal noun. Some grammarians make two forms in English: (a ) The simple form, as, speak, go, hear, before which to is commonly placed, as, to speak; to go; to hear. (b ) The form of the imperfect participle, called the infinitive in -ing; as, going is as easy as standing.
Webster 1913
split infinitive
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noun an infinitive with an adverb between `to' and the verb (e.g., `to boldly go')