[UK: from the children's books]
1. Small and un-useful, but demonstrating a point. Noddy programs are often written by people learning a new language or system. The archetypal noddy program is hello world. Noddy code may be used to demonstrate a feature or bug of a compiler. May be used of real hardware or software to imply that it isn't worth using. “This editor's a bit noddy.”
2. A program that is more or less instant to produce. In this use, the term does not necessarily connote uselessness, but describes a hack sufficiently trivial that it can be written and debugged while carrying on (and during the space of) a normal conversation. “I'll just throw together a noddy awk script to dump all the first fields.” In North America this might be called a mickey mouse program. See toy program.