Teens, young adults
Short for "fils de pute", literally "son of a bitch". It is most often used as an insult, but sometimes, young adults can use it at the end of a sentence, when they are annoyed and want to exaggerate. It's mainly used when texting, but you can also hear it spoken.
Caution: "fdp" is also a short for "frais de port" (shipping costs).
"Rends-moi mon argent fdp."
"Give me back my money you son of a bitch."