Superiority claimed by landed gentry (4)
I believe the answer is:
edge
'superiority' is the definition.
(I know that edge is a type of superiority)
'claimed by landed gentry' is the wordplay.
'claimed by' indicates a hidden word.
'EDGE' can be found hidden inside 'landed gentry'.
(Other definitions for edge that I've seen before include "Boundary; advantage" , "Bite" , "Rim,border" , "Golden ingot" , "Intense/striking quality" .)