Dictator’s honest sound (6)
I believe the answer is:
strait
'sound' is the definition.
(strait is a kind of sound)
'dictator's honest' is the wordplay.
'dictator's' indicates a 'sounds like' (homophone) clue (as somebody dictating would pronounce the word).
'honest' becomes 'straight' ('straight' can be similar in meaning to 'honest').
'straight' sounds like 'STRAIT'.
(Other definitions for strait that I've seen before include "Narrow channel of the sea joining two larger bodies of water" , "Hardship - narrow passage of water" , "Narrow stretch of sea" , "Sound" , "Narrow or difficult" .)