Dishonesty mostly in government houses (5)
I believe the answer is:
lying
'dishonesty' is the definition.
(lying is a kind of dishonesty)
'mostly in government houses' is the wordplay.
'houses' indicates the answer is hidden within the clue (part of the clue houses the answer).
'LYING' can be found hidden inside 'mostly in government'.
(Other definitions for lying that I've seen before include "Prevaricating" , "Prone - telling porkies" , "Anything but upright" , "Deceit" , "Invention" .)