Big design up front
Big design up front (BDUF) is a software development approach in which the program's design is to be completed and perfected before that program's implementation is started. It is often associated with the waterfall model of software development.
Synonyms for big design up front (BDUF) are big modeling up front (BMUF) and big requirements up front (BRUF). These are viewed as anti-patterns within agile software development.