Armagnac estate houses experts (4)
I believe the answer is:
aces
'experts' is the definition.
(ace is a kind of expert)
'armagnac estate houses' is the wordplay.
'houses' says the answer is hidden in the clue (part of the clue houses the answer).
'ACES' can be found hidden inside 'armagnac estate'.
(Other definitions for aces that I've seen before include "Two will make deuce" , "wartime pilots?" , "winning shots" , "Experts (in their field)" , "Ones or elevens in cards" .)