King with silver engaged in risks in unenlightened times (4,4)
I believe the answer is:
dark ages
'unenlightened times' is the definition.
(period of history)
'king with silver engaged in risks' is the wordplay.
'king' becomes 'K' (abbreviation for king in chess).
'with' is a charade indicator (letters next to each other).
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'engaged in' means one lot of letters goes inside another.
'risks' becomes 'dares' (I've seen this before).
'k'+'ag'='kag'
'kag' placed into 'dares' is 'DARK AGES'.
'in' is the link.
(Other definitions for dark ages that I've seen before include "Period after the fall of Rome" , "Period c AD500-1100" , "Period after the fall of the Roman Empire" , "Period of European history from 5c to 9c or 12c" , "Relatively unproductive time" .)