To my knowledge there have been no official efforts to support Clojure so far. Griffon 2.x requires the use of specific class types (Controller, Model, View, etc) plus the use of annotation processors make life easier (although not strictly required). These could make your Clojure code look less idiomatic and more Java-ish.

However there was an experimental branch of 2.x with Frege support, which means Clojure is certainly doable.