The Brief: On social media NOOMF is an acronym for "not one of my followers."

Bluesquiggle
DEEP DIVE

NOOMF is the opposite of OOMF. It’s commonly used on stan Twitter to talk about someone who doesn’t follow you. It can be used disparagingly or neutrally to refer to someone who isn’t following a tweet’s author or to call out one of their followers to say “not one of my followers (doing X thing).”

https://twitter.com/snakewithsword/status/1361784127666540544