Fluency is understanding what you hear and being able to
answer quickly.
Fluency is having a vocabulary and grasp of grammar that
is as good as a native speaker or almost as good as a
native speaker.
Fluency is being able to work in the language at a high
level. At a high level means you could comfortably handle
making presentations, meeting clients and accurately
convey all the information you need to convey to clients in
the language without using google translate.