A quiet look by male bachelor shows confidence (6)
I believe the answer is:
aplomb
'confidence' is the definition.
(I've seen this before)
'a quiet look by male bachelor' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'look' becomes 'lo' (archaic exclamation meaning 'look!').
'by' is a charade indicator (letters next to each other).
'male' becomes 'm' (common abbreviation).
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'a'+'p'+'lo'+'m'+'b'='APLOMB'
'shows' acts as a link.
(Other definitions for aplomb that I've seen before include "coolness is required" , "Self-satisfied poise" , "Pompous dignity or poise" , "'Poise, sang-froid (6)'" , "Calm self-assurance and poise" .)