A well known surname, like Hill (5)
I believe the answer is:
astor
'a well known surname' is the definition.
The definition suggests a singular noun which matches the answer.
'like hill' is the wordplay.
'like' becomes 'as'.
'hill' becomes 'tor' (tor is a kind of hill).
'as'+'tor'='ASTOR'
Can you help me to learn more?
(Other definitions for astor that I've seen before include "See 2" , "First woman to sit in the House of Commons, d. 1964" , "Nancy --, one-time MP" , "Nancy ---, first woman MP" , "First female MP" .)