Annual fee expected to overcome (6)
I believe the answer is:
subdue
'overcome' is the definition.
(synonyms)
'annual fee expected' is the wordplay.
'annual fee' becomes 'sub' (I am not sure about this - if you are sure you should believe this answer much more).
'expected' becomes 'due' (similar in meaning).
'sub'+'due'='SUBDUE'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for subdue that I've seen before include "Vanquish" , "Overcome or inhibit" , "'Quieten, bring under control (6)'" , "Bring under control, tame" , "Overcome, bring under control" .)