Bliss in derelict house elevated river swamps (8)
I believe the answer is:
euphoria
'bliss' is the definition.
(I've seen this in another clue)
'in derelict house elevated river swamps' is the wordplay.
'in derelict' becomes 'e' (I can't justify this - if you can you should give a lot more credence to this answer).
'house' becomes 'ho' (abbreviation for house).
'elevated' becomes 'up' (raised up).
'river' becomes 'ria'.
'swamps' means one lot of letters goes inside another (inserted letters are covered up or swamped).
'up'+'ria'='upria'
'ho' placed inside 'upria' is 'uphoria'.
'e'+'uphoria'='EUPHORIA'
Can you help me to learn more?
(Other definitions for euphoria that I've seen before include "feeling good?" , "transport" , "Intense feeling of happiness" , "Feeling of great elation and joy" , "Rapture" .)