Head of bank, reckless and cocky (5)
I believe the answer is:
brash
'cocky' is the definition.
(thesaurus)
'head of bank reckless' is the wordplay.
'head of' suggests taking the first letters.
'reckless' becomes 'rash' ('rash' can be a synonym of 'reckless').
The initial letter of 'bank' is 'b'.
'b'+'rash'='BRASH'
'and' acts as a link.
(Other definitions for brash that I've seen before include "Cocksure" , "Very loud, flashy or showy" , "forward" , "Pushy" , "Offensively loud" .)