The subtleties of smart neckwear (8)
I believe the answer is:
niceties
'the subtleties' is the definition.
('nicety' can be a synonym of 'subtlety')
'smart neckwear' is the wordplay.
'smart' becomes 'nice' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'neckwear' becomes 'ties' (I've seen this in another clue).
'nice'+'ties'='NICETIES'
'of' is the link.
Can you help me to learn more?
(Other definitions for niceties that I've seen before include "refinement" , "Degrees of precision" , "Fine points" , "Shades" , "Delicacy" .)