FIML is an acronym that stands for Functional Interpersonal Meta Linguistics.
FIML in one gif (best with sound off):
FIML is a form of analytical psychotherapy done between two people, neither of whom needs any formal training in psychotherapy. It is designed to optimize communication and psychological well-being.
FIML is a technique that uses real-time, real-world communication data to clear up mistaken psychological interpretations that may have been held for many years or that may have just arisen.
By clearing up many small mistaken interpretations between partners, FIML gradually clears up the psychological bases of those misinterpretations. In this way, FIML optimizes the communication and psychologies of both partners.
For a basic description of how to do FIML see: How to do FIML.
For more information about the theory and practice of FIML, please see other posts on this site, most of which are concerned with FIML in one way or another.