Is a split infinitive bad grammar?

Although split infinitives were traditionally viewed as ungrammatical, they are now largely viewed as acceptable and are sometimes necessary.

You may want to avoid them where possible in academic or professional environments, as some may still view them negatively, but you don’t need to avoid them entirely. Split infinitives can provide emphasis, and moving the adverb can sometimes result in an ungrammatical or unclear sentence.

For example, in “Gemma asked Kamil to quietly shut the door,” moving “quietly” either results in an awkwardly worded sentence or makes it unclear: does “quietly” refer to the volume of Gemma’s voice or the way she wants Kamil to shut the door?