(bound? & vars)
Returns true if all of the vars provided as arguments have any bound value, root or thread-local. Implies that deref'ing the provided vars will succeed. Returns true if no vars are provided.
user=> (def foobar)
#'user/foobar
user=> (bound? #'foobar)
false
user=> (def boing 10)
#'user/boing
user=> (bound? #'boing)
true
user=> (defn plus3 [n] (+ 3 n))
#'user/plus3
user=> (bound? #'plus3)
true