Clipper is a programming language, and it is also a compiler. The programming language is a superset of dBASE III+, and also shares some features with C/C++ and Smalltalk. It is a general-purpose, high-level programming language well suited to corporate and commercial applications development.
Clipper is also a compiler product. The Clipper compiler is (by definition) a fully conformant implementation of the Clipper programming language for IBM-PC-type personal computers running DOS-like operating systems.
There are other Clipper implementations, that have varying capabilities and run on platforms other than MS-DOS.
Q: Isn’t Clipper obsolete?
A: Clipper, the commercial compiler for DOS ? Well, it’s definitely stopped evolving; the owner company has announced that 5.3 will be the last significant release and only maintenance patches will be forthcoming.
There is a lot of maintenance work for good Clipper programmers. And when you do write that occasional new DOS program (some of us still do!), Clipper is an outstanding choice. But for most programmers in business today, yeah, there are really not too many applications that you would write from scratch with Clipper.
Clipper, the language? Definitely not obsolete. Clipper clones, improvements, and adaptations; commercial or not, are everywhere.
Note : Gathered from here.