Scrutiny of very particular year sister joined (8)
I believe the answer is:
analysis
'scrutiny' is the definition.
(thesaurus)
'very particular year sister joined' is the wordplay.
'very particular' becomes 'anal' (I can't explain this - if you can you should believe this answer much more).
'year' becomes 'y'.
'sister' becomes 'sis' (synonyms).
'joined' is a charade indicator (letters next to each other).
'anal'+'y'+'sis'='ANALYSIS'
'of' is the link.
Can you help me to learn more?
(Other definitions for analysis that I've seen before include "Dissection and examination" , "Detailed interpretation" , "Criticism" , "Study of mind" , "Examination to determine component parts" .)