Composure of celebrated female, one sitting in bar (9)
I believe the answer is:
sangfroid
'composure' is the definition.
(thesaurus)
'celebrated female one sitting in bar' is the wordplay.
'celebrated' becomes 'sang' (singing might be done as part of a celebration).
'female' becomes 'f' (abbreviation).
'one' becomes 'i' (Roman numeral).
'sitting in' is an insertion indicator.
'bar' becomes 'rod' (both can mean a pole or stick).
'i' inserted into 'rod' is 'roid'.
'sang'+'f'+'roid'='SANGFROID'
'of' acts as a link.
(Another definition for sangfroid that I've seen is " Cool".)