Disadvantaged by worker in charge appointed by media boss (11)
I believe the answer is:
handicapped
'disadvantaged' is the definition.
('handicap' can be a synonym of 'disadvantage')
'worker in charge appointed by media boss' is the wordplay.
'worker' becomes 'hand' (hand is a kind of worker).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'appointed by' becomes 'app' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'media boss' becomes 'ed' (short for editor).
'hand'+'ic'+'app'+'ed'='HANDICAPPED'
'by' is the link.
Can you help me to learn more?
(Other definitions for handicapped that I've seen before include "Disabled" , "rated adversely" .)