Finishes post from top to bottom (4)
I believe the answer is:
ends
'finishes' is the definition.
('end' can be a synonym of 'finish')
'post from top to bottom' is the wordplay.
'post from top' becomes 's' (I can't justify this - if you can you should believe this answer much more).
'to' says to put letters next to each other (I've seen this in other clues).
'bottom' becomes 'end' (I've seen this in other clues).
's' put after 'end' is 'ENDS'.
Can you help me to learn more?
(Other definitions for ends that I've seen before include "deaths" , "'Goals, objectives (4)'" , "They may justify the means" , "Desired results" , "See 8" .)