Concatenative (stack-based) ProgrammingLanguage
Is Forth as powerful as Lisp?
But it's arguably simpler than Lisp.
So like Lisp (and Smalltalk) it scales up from very simple, regular foundation, to being surprisingly powerful. That means it has the same kind of "multiplier effect" as Lisp. Perhaps its multiplier effect is, indeed, even greater than Lisp's, given where you start and where you can end up.
But Forth makes explicit things like stack management that Lisp does for you automatically. So it confronts you with more low level thinking that Lisp hides.
To the best of my knowledge, Forth doesn't have either higher-order functions or macros, which would seem to limit its expressivity. And, from what I've seen, Forth doesn't have stacks as first class citizens either, and different variants of Forth seem to build in extra control structures and extra complex data-structures, suggesting that Forth can't build these within itself.
I've played a bit with Joy, which is Forth-like concatenative language that does have first class code-blocks and combinators, which are the equivalent of higher-order functions. Possibly Joy is as powerful as Lisp. Though I've found it more mind-bending to try to use it.