Old knight, artist and old actress (7)
I believe the answer is:
raleigh
'old knight' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'artist and old actress' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'and' is a charade indicator (letters next to each other).
'old actress' becomes 'leigh' (I've seen this before. I am not sure about the 'old' bit.).
'ra'+'leigh'='RALEIGH'
Can you help me to learn more?
(Other definitions for raleigh that I've seen before include "SECOND PART OF 12 ACROSS" , "Sir Walter . . . . . . ., potato and tobacco importer" , "Elizabethan courtier" , "Sir Walter --, courtier" , "navigator and author" .)