An attack on the integrity of a person is disgraceful (9)
I believe the answer is:
aspersion
'an attack' is the definition.
(I know that aspersion is a type of attack)
'the integrity of a person is disgraceful' is the wordplay.
'a person is' can be anagrammed to 'ASPERSION'.
Though, I'm not sure how the anagram is indicated.
'on' acts as a link.
Can you help me to learn more?
(Other definitions for aspersion that I've seen before include "Defamatory suggestion" , "Cast this slur" , "No praises (anag) - disparaging remark" , "Slander" , "Attack on reputation" .)