The acronym "AF IN BH" is commonly used in social media slang, particularly on platforms like Twitter, Facebook, and Instagram. It stands for "As F*** In Big Head", which is often employed to describe someone who is extremely arrogant or full of themselves. While there isn't a direct synonym for this phrase, there are alternative expressions that can convey a similar meaning. Some possible options include "conceited", "egotistical", "self-important", "arrogant" or "narcissistic". These words all capture the essence of someone who possesses an inflated sense of self-worth or exaggerated ego, which aligns with the connotation of "AF IN BH."