neologism (n.)

1772 (in a translation from French), "practice of innovation in language, the use of new words or old words in new senses," from French néologisme (18c.), from neo- "new" (see neo-) + Greek logos "word" (see Logos) + -ism. Meaning "new word or expression" is from 1803. Neological "characterized by new words or phrases" is attested from 1754. Related: Neologically.