Respect quartet I left in town (8)
I believe the answer is:
civility
'respect' is the definition.
(thesaurus)
'quartet i left in town' is the wordplay.
'quartet' becomes 'IV' (roman numerals for four).
'left' becomes 'L' (common abbreviation).
'in' means one lot of letters goes inside another.
'town' becomes 'city' (I've seen this in other clues).
'iv'+'i'+'l'='ivil'
'ivil' put within 'city' is 'CIVILITY'.
(Other definitions for civility that I've seen before include "Formal politeness and courtesy" , "Courteousness" .)