“You held me down, but I got up
Already brushing off the dust”

Katy Perry – Roar Lyrics on LyricsMode
EXPLANATION
People put her down and she picked herself up and is taking off the dust from the ground because she has "risen".
EXPLANATION
Many people criticize her, she won't let herself lose to them, she will rise and she will put her name up again.
EXPLANATION
She letting the hater know that no matter how many time or how hard they push her down,it's just a waste of time because she will always get up and getting stronger and stronger each time.
EXPLANATION
She is saying that the person who took advantage of her held her down by putting pressure on her and now she is letting that person know that she is not taking it anymore and she's done with it.