BFF definition: Informal. plural bffs, BFFs
- a person’s best friend, typically a girl’s (sometimes used facetiously)
- one’s close associate, ally, or supporter
“All the literati keep an imaginary friend.” — W. H. Auden
“I still think most writers are just kids who refuse to grow up. We’re still playing imaginary games, with our imaginary friends.” — Ian Rankin