Fastidiousness (4,3,6)
I believe the answer is:
spit and polish
'fastidiousness' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for spit and polish that I've seen before include "exaggerated smartness" , "(Close attention to) military discipline" , "Boots could profit from this" , "Punctilious military discipline" , "Punctilious attention to cleanliness, discipline, etc" .)