Brilliant Lucy's cut short - essential part of presenting team initially (6)
I believe the answer is:
lucent
'brilliant' is the definition.
(I've seen this before)
'lucy's cut short essential part of presenting team initially' is the wordplay.
'cut short' means to remove the last letter.
'essential part of' means to look at the middle letters.
'initially' says to take the initial letters.
The central letters of 'presenting' are 'en'.
The first letter of 'team' is 't'.
'lucy' with its last letter removed is 'luc'.
'luc'+'en'+'t'='LUCENT'
(Other definitions for lucent that I've seen before include "'Lambent, luminous (6)'" , "Softly bright or radiant" , "Brilliant" , "Shining" .)