1. [very common] The lowest form of cracker; script kiddies do mischief with scripts and rootkits written by others, often without understanding the exploit they are using. Used of people with limited technical expertise using easy-to-operate, pre-configured, and/or automated tools to conduct disruptive activities against networked systems. Since most of these tools are fairly well-known by the security community, the adverse impact of such actions is usually minimal.
2. People who cannot program, but who create tacky HTML pages by copying JavaScript routines from other tacky HTML pages. More generally, a script kiddie writes (or more likely cuts and pastes) code without either having or desiring to have a mental model of what the code does; someone who thinks of code as magical incantations and asks only “what do I need to type to make this happen?”