Moderate meant to control disposition (11)
I believe the answer is:
temperament
'disposition' is the definition.
(I know that disposition can be written as temperament)
'moderate meant to control' is the wordplay.
'moderate' becomes 'temper' (synonyms).
'to control' indicates anagramming the letters.
'meant' is an anagram of 'ament'.
'temper'+'ament'='TEMPERAMENT'
(Other definitions for temperament that I've seen before include "Piano tuning; character" , "A person's nature as it affects behaviour" , "Personality" , "Disposition; tuning adjustment" , "Person's nature; adjustment in piano tuning" .)