Study broken nails, say (8)
I believe the answer is:
analysis
'study' is the definition.
(analysis is a kind of study)
'broken nails say' is the wordplay.
'broken' indicates anagramming the letters.
'nails'+'say'='nailssay'
'nailssay' with letters rearranged gives 'ANALYSIS'.
(Other definitions for analysis that I've seen before include "See 15" , "resolution" , "Breakdown (for study)" , "Examination of structure of problem" , "Detailed interpretation" .)