Splendid display by English side City (7)
I believe the answer is:
pompeii
'city' is the definition.
(Pompeii is an example)
'splendid display by english side' is the wordplay.
'splendid display' becomes 'pomp' (I've seen this in another clue).
'by' says to put letters next to each other.
'english' becomes 'e' (abbreviation).
'side' becomes 'ii' (I can't explain this - if you can you should believe this answer much more).
'pomp'+'e'+'ii'='POMPEII'
Can you help me to learn more?
(Other definitions for pompeii that I've seen before include "town coming to a terrible end" , "Ruined Roman town" , "Town buried by Vesuvius 1st century a.d." , "Roman town buried by Vesuvius" , "Ancient city buried when Vesuvius erupted" .)