The phrase 'Fast Friends' is used to describe good, loyal friends.
Example of Use: "The two of them had been fast friends since college."
Interesting fact about Fast Friends
Although many believe that the idiom 'fast friends' means friends who developed a liking for one another quickly, the term is actually a shortened form of 'steadfast friends.' The origin of the idiom 'fast friends' comes from an even older version of the word 'steadfast' – Old English triewe meaning faithful, trustworthy, and steady in adhering to promises or friends.
