An acronym for : My Dearest Friend For Life. The highest form of friendship and a loving bond between two people. They would take bullets for one another. They are willing to be weird and crazy around each other... no questions asked. Unbreakable bond... they always end up back together. Fate reunites them no matter where they are. They are friends that are comfortable being with each other and doesn’t feel the urge to have small talk.. their presence is enough. If you find your MDFFL keep and hold them close.