River choked by sediment not so nice now (6)
I believe the answer is:
spoilt
'river choked by sediment not so nice now' is the definition.
I can't judge whether this defines the answer.
'river choked by sediment' is the wordplay.
'river' becomes 'Po' (the river Po in Italy).
'choked by' is an insertion indicator (I've seen this in other clues).
'sediment' becomes 'silt' (I've seen this in another clue).
'po' put within 'silt' is 'SPOILT'.
Can you help me to learn more?
(Other definitions for spoilt that I've seen before include "Went off" , "Overindulged" , "Made a mess of" , "Deprived" , "injured" .)