Itself an invented word used exclusively pejoratively to dismiss newly coined words. Usually used to express distaste for words inconvenient to one's ideology.
An adverb meaning of, from or related to newly created words. It stems from Neology which in turn comes from the French ‘neologisme’ meaning a newly created word.
Basically, a new word that comes into a language through creatively using that language. Borrowed words from other languages and dialects are not neologisms.