A lot possibly said for a king (5)
I believe the answer is:
'a king' is the definition.
'a lot possibly said' is the wordplay.
'a lot' becomes 'm' ().
'possibly' is an anagram indicator.
'said' anagrammed gives 'idas'.
'for' is the link.
(Other definitions for midas that I've seen before include "Greek mythological king with money-making touch", "I'm sad (anag) -- king of Phrygia", "Everything he touched turned to gold", "Golden-touch king", "Mythical king who had the power to turn everything to gold".)