The panache of a trusty leader (5)
I believe the answer is:
style
'the panache' is the definition.
('style' can be a synonym of 'panache')
'of a trusty leader' is the wordplay.
'of' indicates the answer is hidden within the clue.
'STYLE' is hidden within 'trusty leader'.
(Other definitions for style that I've seen before include "Elan" , "Manner; elegance" , "Designate" , "Showy way of life - elegance" , "Fashion - flair" .)