"Kesafat" is a Persian word for Nasty, Disgustingly dirty, morally offensive, and indecent. The low profanity strength level of this word has allowed a public usage. Analogous words such as "Lajan" (Literally for Black Mud) or "goh" (feces) are normally followed or preceded by "kesafat" for extra invigoration.
a) ajab kesafati hasti ha!
What a dirty person you are!