Katy Perry hit with the lyric "Louder, louder than a lion" (4)
I believe the answer is:
roar
'katy perry hit with the lyric louder louder than a lion' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for roar that I've seen before include "cheer" , "Yell" , "Cry (as a lion)" , "Deep-throated cry" , "Zoom - prolonged cry" .)