Legislative assembly to fade away over time (4)
I believe the answer is:
diet
'legislative assembly' is the definition.
(diet is a kind of legislative assembly)
'fade away over time' is the wordplay.
'fade away' becomes 'die' (I've seen this in other clues).
'over' is a charade indicator (letters next to each other).
'time' becomes 't'.
'die'+'t'='DIET'
'to' is the link.
(Other definitions for diet that I've seen before include "Food - parliament" , "Supposed slimming plan" , "Regime followed by slimmer" , "The kinds of food one eats" , "Regimen for eating" .)