Lords and ladies look to get on (7)
I believe the answer is:
peerage
'lords and ladies' is the definition.
(I've seen this before)
'look to get on' is the wordplay.
'look' becomes 'peer' (peering is a kind of looking).
'to get on' becomes 'age' ('age' can be a synonym of 'get on').
'peer'+'age'='PEERAGE'
(Other definitions for peerage that I've seen before include "Book of the nobility" , "Lordly group" , "The nobility en masse" , "Ranks of the nobility" , "The whole of the British nobility" .)