Manor man makes genuine impression (8)
I believe the answer is:
hallmark
'genuine impression' is the definition.
(I've seen this before)
'manor man' is the wordplay.
I cannot really understand how this works, but
'man' could be 'mark' and 'mark' is found within the answer.
The remaining letters 'hall' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'makes' acts as a link.
Can you help me to learn more?
(Other definitions for hallmark that I've seen before include "It indicates the standard of precious metals" , "Assay stamp" , "Standard sign for silver" , "Assay-stamp" , "Distinguishing characteristic - indicates standard of gold, silver etc." .)