Dictator's wet in command (5)
I believe the answer is:
reign
'command' is the definition.
(thesaurus)
'dictator's wet' is the wordplay.
'dictator's' shows a homophone (sound like) (as somebody dictating would pronounce the word).
'wet' becomes 'rain' (I've seen this in other clues).
'rain' sounds like 'REIGN'.
'in' is the link.
(Other definitions for reign that I've seen before include "time in power" , "Be champion" , "Dominion" , "period in power" , "Period of a monarchy" .)