One of the first kdramas I watched was KBS’s “Full House.”  The lead actor, Bi-rain, and lead actress, Song Hye-kyo, said “aja aja- fighting” many times throughout the tv series. 

I asked my friend who is from Korea, and she said that they do say “fighting”... pronounced “hwaiting” or just “aja” with the added movement of the arm as seen in this clip from KBS’s “Full House.” 

As seen in the clip, “aja” or “hwaiting/fighting” is a way of saying “you can do it.”  Many times you see an actor or actress in a kdrama say it to him or herself to encourage self-confidence within! 

May we do the same ^_^.  Aja Fighting!