Repair this originally rather tatty top (6*)
I believe the answer is:
'top' is the definition.
(I've seen this before)
'repair this originally rather tatty' is the wordplay.
'repair' indicates anagramming the letters (letters are fixed or repaired).
'originally' suggests taking the first letters.
The initial letters of 'rather tatty' is 'rt'.
'this' with letters rearranged gives 'tshi'.