Whitman, perhaps, capturing English hotel's opulence (6)
I believe the answer is:
wealth
'opulence' is the definition.
(I've seen this in another clue)
'whitman perhaps capturing english hotel's' is the wordplay.
'whitman perhaps' becomes 'Walt' (poet Walt Whitman).
'capturing' means one lot of letters goes inside another.
'english' becomes 'e' (abbreviation).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'walt' placed around 'e' is 'wealt'.
'wealt'+'h'='WEALTH'
(Other definitions for wealth that I've seen before include "Assets" , "capital" , "Riches, worldly goods" , "Possessions and resources" , "Abundance of resources" .)