Who coined the term neolithic?

Sir John Lubbock.

"In 1865 Lubbock published what was probably the most influential archaeological text book of the 19th Century, Pre-historic Times, as Illustrated by Ancient Remains, and the Manners and Customs of Modern Savages, and was responsible for inventing the names Palaeolithic and Neolithic to denote the Old and New Stone Ages respectively."

https://en.wikipedia.org/wiki/John_Lubbock,_1st_Baron_Avebury

"The term Neolithic derives from the Greek νεολιθικός, neolithikos, from νέος neos, "new" + λίθος lithos, "stone", literally meaning "New Stone Age." The term was invented by Sir John Lubbock in 1865 as a refinement of the three-age system."

https://en.wikipedia.org/wiki/Neolithic

https://en.wikipedia.org/wiki/Three-age_system