For rousing passion, unfinished symphony by Beethoven eclipses his fourth (6)
I believe the answer is:
erotic
'for rousing' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for erotic that I've seen before include "love poem" , "Loving composition" , "Calculated to arouse sexual desire" , "Designed to arouse sexual desire" , "Relating to sexual desire" .)