Knight at home touring large European capital (6)
I believe the answer is:
dublin
'european capital' is the definition.
(I've seen this before)
'knight at home touring large' is the wordplay.
'knight' becomes 'dub' (to dub can mean to knight someone**).
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'touring' means one lot of letters goes inside another (touring can mean going round).
'large' becomes 'l'.
'dub'+'in'='dubin'
'dubin' going around 'l' is 'DUBLIN'.
(Other definitions for dublin that I've seen before include "European city" , "Capital of Ireland" , "Capital of Eire" , "City of 1 across" , "European capital" .)