When people greet other persons, it's a word employed with pronoun "ma" in an expression which means "how are you?".
: "Ouaich/Wesh ma gueule, tranquille? La forme ? or : "Bien ma gueule cousin ?"
Nota bene : You can replace this word by "couille" preceded by "ma" but this sentence could take the meaning of "How are you buddy ?". You have too : "Bien ou quoi ?"