FNF most commonly stands for:

• "Followers and Following" used on Instagram referring to the count or ratio of followers to people you follow.
• "Friday Night Funkin'" which is a popular open-source rhythm video game released in 2020.
• "Friends and Family," often used in contexts like PayPal for sending money without transaction fees.
• "Full and Final" settlement, especially in employment contexts for finalizing dues after leaving a job.
• In online dating, it can mean "Friends with No Benefits" or "Fun and Flirty" depending on context.

The exact meaning depends on the context in which it's used. For example, on social media like Instagram, it's often about followers; among gamers, it's likely about the rhythm game; in employment, it often means full and final settlement; and in casual relationships, it can mean friends without romantic benefits.

Let me know if you want details on any specific meaning or context.