Message about father being competent (7)
I believe the answer is:
capable
'competent' is the definition.
(synonyms)
'message about father' is the wordplay.
'message' becomes 'cable' (as in sending a cable to someone).
'about' means one lot of letters goes inside another.
'father' becomes 'pa' (pa can mean dad or father).
'cable' going around 'pa' is 'CAPABLE'.
'being' acts as a link.
(Other definitions for capable that I've seen before include "accomplished" , "Able, proficient" , "Able, competent" , "Of a person, competent" , "Efficient" .)