Define Inb4 Meaning

Generally used on internet forums, inb4 refers to a user posting a reply to a message/topic "before" another user posts an obvious response. When used appropriately, inb4 is followed by a word or short phrase that the user knows will eventually appear in the topic conversation.

An internet term that is short for "in before" used when someone replies to something before something that they anticipate to happen eventually happens.

You are calling something, you bet that it will happen.

a 4chan phrase that means "in thread before (b4) it 404's (gets deleted (you get a 404 error message when a thread is deleted))

Started on MLPForums, this refers to posting in a topic before ghostfacekiller39 that speaks badly of the character Rarity from My Little Pony: Friendship is Magic. ghostfacekiller39 is perhaps the most dedicated Rarity fan on the forums, and he's always quick to defend her when the need arises.