Current tribute defends quiet expertise (14)
I believe the answer is:
accomplishment
'expertise' is the definition.
(accomplishment can mean skill or expertise)
'current tribute defends quiet' is the wordplay.
'current' becomes 'ac' (alternating current).
'tribute' becomes 'compliment' (to compliment someone is to pay tribute to them).
'defends' is an insertion indicator (inserted letters are held or defended).
'quiet' becomes 'sh' (both can be said to tell someone to be quiet).
'compliment' enclosing 'sh' is 'complishment'.
'ac'+'complishment'='ACCOMPLISHMENT'
(Other definitions for accomplishment that I've seen before include "exploit" , "Successful achievement" , "Something achieved" , "Skill" .)