Meaning

noun a programmer who breaks into computer systems in order to steal or change or destroy information as a form of cyber-terrorism

noun a writer of science fiction set in a lawless subculture of an oppressive society dominated by computer technology

noun a genre of fast-paced science fiction involving oppressive futuristic computerized societies

originFrom cyber- + -punk, coined by American writer and software developer Bruce Bethke as the title of a 1983 short story, and later popularized by Gardner Dozois.

Etymology from Wiktionary, CC BY-SA 3.0