Short dog has time (4)
I believe the answer is:
curt
'short' is the definition.
(I know that short can be written as curt)
'dog has time' is the wordplay.
'dog' becomes 'cur' (both can mean a despicable person).
'has' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'cur'+'t'='CURT'
(Other definitions for curt that I've seen before include "Brief and terse" , "Rudely abrupt, short" , "Brusque, abrupt in speech" , "Rudely brief" , "Brief and brusque" .)