Repair fine kitchen vessel without its lid (6)
I believe the answer is:
fettle
'repair' is the definition.
(thesaurus)
'fine kitchen vessel without its lid' is the wordplay.
'fine' becomes 'f' (abbreviation e.g. condition of old coins, books).
'kitchen vessel' becomes 'kettle' (vessel used in a kitchen).
'without its lid' means to remove the first letter (in a down clue, lid could mean the top letter).
'kettle' with its initial letter removed is 'ettle'.
'f'+'ettle'='FETTLE'
(Other definitions for fettle that I've seen before include "Be in fine . . . . . . to be in excellent form" , "Condition or trim, often fine" , "Condition (usually fine)" , "Be in fine . . . . . . to be in good condition (6)" , "Condition, trim - best when fine" .)