Quality that arouses pity (6)
I believe the answer is:
pathos
'quality that arouses pity' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for pathos that I've seen before include "pitiful feeling" , "Quality eliciting pity and sympathy" , "Quality that arouses pity or sadness" , "Quality evoking pity or sadness" , "Tragic air" .)