The Common Lisp object-system does not use the more imperative message-sending / virtual method calling. It favors "generic functions of related methods" instead - thus this is kind of an integration of function-centric programming into the traditional view of OOP where methods belong to classes.
Common Lisp is multi-paradigm and can be written to write functional code. It is the direct descendant of LISP which was the first functional language after all. Yes, Scheme and the like are more functional but CL is still far more functional than most other languages.
Imperative relates to coding style - I can equally write imperative or recursive code in Java.
It's not a functional programming language. It's an object-oriented imperative language.