Exceed bold self-confidence of those in authority (3,5)
I believe the answer is:
top brass
'those in authority' is the definition.
(I've seen this before)
'exceed bold self-confidence' is the wordplay.
'exceed' becomes 'top' (synonyms).
'bold self-confidence' becomes 'brass' (I've seen this before).
'top'+'brass'='TOP-BRASS'
'of' is the link.
(Other definitions for top brass that I've seen before include "management" , "Authorities" , "Senior officers" , "Highest rankings in the armed forces" , "military leaders" .)