The Collaborative International Dictionary of English v.0.48:

free-associate \free-associate\ v. i. (psychoanalysis)
   to express one's thoughts, ideas, impressions, etc. in an
   unplanned and unstructured way, allowing each thought or idea
   to prompt recollection of the next one. It is a process used
   in psychotherapy.

   Syn: associate freely.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

free-associate
    v 1: associate freely; "Let's associate freely to bring up old
         memories"