Pity person's corrupt tendency (10)
I believe the answer is:
propensity
'tendency' is the definition.
(I know that propensity is a type of tendency)
'pity person's corrupt' is the wordplay.
'corrupt' is an anagram indicator (a corrupted spelling of the word).
'pity'+'person'='pityperson'
'pityperson' with letters rearranged gives 'PROPENSITY'.
(Other definitions for propensity that I've seen before include "Bent" , "Inclination; tendency" .)