Advisers ultimately in moral decline (7)
I believe the answer is:
descent
'decline' is the definition.
(synonyms)
'advisers ultimately in moral' is the wordplay.
'ultimately' says to take the final letters.
'in' indicates putting letters inside.
'moral' becomes 'decent'.
The final letter of 'advisers' is 's'.
's' placed inside 'decent' is 'DESCENT'.
(Other definitions for descent that I've seen before include "Roots" , "Coming down" , "Derivation from an ancestor - going down" , "Drop" , "line" .)