Interestingly, Lisp tends to be more closely related to modern imperative or OOP languages than modern FP languages most of the time (although this is very much

Interestingly, Lisp tends to be more closely related to modern imperative or OOP languages than modern FP languages most of the time (although this is very much a matter of dialect, as Clojure and Scheme code tend to resemble FP much more than CL and Elisp code do). Lisp had some ideas influential to FP that also made their way into other types of programming (garbage collection, closures, etc.), but things which are considered a modern necessity for functional programming are not present in most dialects of Lisp (like immutability of data, at least by default, currying, etc.). In fact, most Lisp dialects don't even have first-class functions (in the sense that variables and functions are stored in totally different namespaces), which even languages like C# support. So to call Lisp 'functional' is a bit of a stretch, despite the large divides between different dialects and the multi-paradigm abilities of those languages, but that's not to say that it wasn't hugely instrumental in the onset of functional programming.