Feed the kitty upset Vietnamese houses (4)
I believe the answer is:
ante
'feed the kitty' is the definition.
(I've seen this in another clue)
'upset vietnamese houses' is the wordplay.
'upset' is a reversal indicator.
'houses' indicates the answer is hidden within the clue (part of the clue houses the answer).
'etna' can be found hidden inside 'vietnamese'.
'etna' reversed gives 'ANTE'.
(Other definitions for ante that I've seen before include "Opening bet" , "early payment" , "Initial bet" , "not post" , "Preposition meaning before" .)