With lisp you stop thinking about syntax rules anymore (because the program is in a very simple form) so you can focus purely on semantics. Some things, like you say, are too overloaded in Clisp, for example:

  (defun averagenum 
    (n1 n2 n3 n4)
    (/ ( + n1 n2 n3 n4) 4))

Clojure recognizes this goo problem and expresses the parameters in a vector instead of how Clisp does it in a list

  (defn averagenum 
    [n1 n2 n3 n4]
    (/ ( + n1 n2 n3 n4) 4))

Helps a lot.