Old suite composed in isolation (8)
I believe the answer is:
solitude
'isolation' is the definition.
(I've seen this before)
'old suite composed' is the wordplay.
'composed' indicates anagramming the letters.
'old'+'suite'='oldsuite'
'oldsuite' is an anagram of 'SOLITUDE'.
'in' acts as a link.
(Other definitions for solitude that I've seen before include "Lone state" , "Privacy" , "Avoiding company" , "Absence of company" , "Lone condition" .)