Boy reporter's stint inexcusably deficient (6)
I believe the answer is:
tintin
'boy reporter's' is the definition.
(character in comics by Herg)
'stint inexcusably deficient' is the wordplay.
'deficient' says the answer is hidden in the clue (some letters in the clue must be removed).
'TINTIN' can be found hidden inside 'stint inexcusably'.
(Other definitions for tintin that I've seen before include "Herge's adventurer" , "cartoon character" , "Comic character" , "Herge's adventurous young Belgian reporter" , "Herge's cartoon hero" .)