River estuary flounders - a source of riches for the nation? (8)
I believe the answer is:
treasury
'a source of riches for the nation?' is the definition.
I can't judge whether this defines the answer.
'river estuary flounders' is the wordplay.
'river' becomes 'r' (abbreviation for river).
'flounders' indicates an anagram (I've seen 'floundering' mean this (letters flounder or move around)).
'r'+'estuary'='restuary'
'restuary' is an anagram of 'TREASURY'.
Can you help me to learn more?
(Other definitions for treasury that I've seen before include "British Department of Finance" , "thesaurus" , "Exchequer - store for valuables" , "The funds of a state" , "Bank" .)