Waste a long time languishing here? (7)
I believe the answer is:
dungeon
'languishing here?' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'waste a long time' is the wordplay.
'waste' becomes 'dung' (dung is a kind of waste).
'a long time' becomes 'eon' (eon is a kind of long time).
'dung'+'eon'='DUNGEON'
Can you help me to learn more?
(Other definitions for dungeon that I've seen before include "Eg, the Black Hole of Calcutta" , "Dark prison cell" , "Place of confinement underground" , "Keep" , "Prison cell, often underground" .)