F9

When someone says something is "f9," they are saying it is OK (most common) or attractive (more uncommon). The term combines "f" with the "ine" part of "nine" (9).

People may use f9 by itself or within a sentence online or in emails. It saves two whole characters, but some slang-savvy people still find it useful.

Often, people use it when describing how they are feeling, such as, "I feel f9." Less common is when people use it to describe attractiveness, such as "He's dumb, but I think he's f9."