> Every dictionary definition of the word I’m looking at right now includes the words “original”, “originality”, or “not imitated.”

Citing dictionary definitions just shifts your argument from one word whose meaning you didn't define to another word whose meaning you haven't defined. Is the Mona Lisa original? It's not the first oil painting, nor the first portrait, nor even the first painting of an Italian noblewoman made in the renaissance style. Yet it's commonly considered to be creative despite being imitative and unoriginal in all those previously mentioned aspects. What definition of original can you then make that simultaneously includes the Mona Lisa, is mutually exclusive with any imitation, and excludes the "majority of humans".