Whoadie is a slang which is used to refer to close friends. This slang originated from New Orleans, Louisiana. New Orleans is divided into wards, people from the same wards used to greet each other as "waaaar-day" which eventually turned into "whoadie." Though many people use this slang to refer to all friends, it's only meant for your closest of friends.
Numerous Hip Hop artists have used this slang in their songs. Young Thug used it in Rich Gang's Imma Ride song, in which he raps, "Lil' whoadie 'bout that action - N*gga playin' with my whoadie, I'ma ride." Drake also used an abbreviated version (Woes) in his song Know Yourself, in which he raps "Runnin' through the 6 with my woes."