Lone arrangement around British peer (5)
I believe the answer is:
noble
'peer' is the definition.
(I've seen this in another clue)
'lone arrangement around british' is the wordplay.
'arrangement' indicates anagramming the letters.
'around' means one lot of letters goes inside another.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'lone' is an anagram of 'nole'.
'nole' enclosing 'b' is 'NOBLE'.
(Other definitions for noble that I've seen before include "old British coin" , "Eminent" , "titled person" , "Titled peer of the realm" , "Lord" .)