It's a little korean word that unite EXO Ls from all over the world. It's the first word from a really popular EXO song WOLF- (which everybody says they hate- but secretly listens to it every night before going to bed) To most EXO Ls 'Chogiwa' might mean the word "Wolf" in Korean because of the word's association with EXO's WOLF, however it actually does NOT mean 'wolf'. When rapper- Chanyeol goes CHOGIWAA- it can have a variety of meanings to all EXO Ls. For example: it might mean to them that EXO snatching all number one places in all music shows.
Chogiwa is a Korean word, ( 초기와 in Hangul), but it's meaning is referred to as "WOLF" by EXO-Ls because it is the first word of EXO's song, WOLF. Lots of fans use the word whenever they feel like it, it's like a signal to all EXO-Ls in radar and immediately anyone who knows the word will know that you're a fan of EXO (which will lead to a BIG friendship)
Feel free to watch the music video and have the word stuck in your head FOREVER ^^