Resolution decided on: time to replace top of element (10)
I believe the answer is:
settlement
'resolution' is the definition.
(synonyms)
'decided on time to replace top of element' is the wordplay.
'decided on' becomes 'set' (I've seen this in another clue).
'time' becomes 't' (abbreviation).
'to' says to put letters next to each other (I've seen this in other clues).
'replace' indicates anagramming the letters (I've seen 'replacing' mean this (placing again)).
'top of' means to remove the first letter (I've seen 'top' mean this).
'element' with its first letter taken away is 'lement'.
'lement' is an anagram of 'tlemen'.
't' after 'tlemen' is 'tlement'.
'set'+'tlement'='SETTLEMENT'
(Other definitions for settlement that I've seen before include "Reservation" , "Small colony" , "Subsidence; payment" , "Working out" , "Colony - discharge of debt" .)