Toff with trapped wind seen by island capital (7)
I believe the answer is:
nairobi
'capital' is the definition.
(capital of Kenya)
'toff with trapped wind seen by island' is the wordplay.
'toff' becomes 'nob' (UK slang for a wealthy or upper-class person).
'with' is an insertion indicator.
'trapped wind' becomes 'air' (air is a kind of wind. I am not sure about the 'trapped' bit.).
'seen by' means one lot of letters go next to another.
'island' becomes 'i' (geographical abbreviation).
'nob' enclosing 'air' is 'nairob'.
'nairob'+'i'='NAIROBI'
Can you help me to learn more?
(Other definitions for nairobi that I've seen before include "Kenyan capital" , "The capital of Kenya (7)" , "Foreign capital" , "Flat round object" , "African city" .)