A case of resident saving no time at all? (10)
I believe the answer is:
nominative
'a case' is the definition.
(grammatical case)
'resident saving no time at all?' is the wordplay.
'resident' becomes 'native' (I've seen this before).
'saving' means one lot of letters goes inside another.
'no' becomes 'o' (resembles 0 - 'no' can mean 'zero').
'time at all?' becomes 'min' (I can't explain this - if you can you should give a lot more credence to this answer).
'o'+'min'='omin'
'native' going around 'omin' is 'NOMINATIVE'.
'of' is the link.
(Other definitions for nominative that I've seen before include "case for Latin?" , "Appointed" .)