The marauder finishes up at the far end, possibly lower (7)
I believe the answer is:
prowler
'the marauder' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'finishes up at the far end possibly lower' is the wordplay.
'finishes up' becomes 'p' (I can't explain this - if you can you should believe this answer much more).
'at' means one lot of letters go next to another.
'end' suggests the final letters.
'possibly' indicates anagramming the letters.
The last letter of 'far' is 'r'.
'lower' with letters rearranged gives 'owler'.
'p'+'r'+'owler'='PROWLER'
Can you help me to learn more?
(Other definitions for prowler that I've seen before include "One moving stealthily" , "Person sneaking about with unlawful intentions" , "Person who roams about stealthily" , "Unwanted vagrant" , "Stealthy mover" .)