Fine item’s not quite finished (4)
I believe the answer is:
thin
'fine' is the definition.
(similar in meaning)
'item's not quite finished' is the wordplay.
'item' becomes 'thing' (both can mean an object).
'not quite finished' means to remove the last letter (most but not all of the word).
'thing' with its last letter taken away is 'THIN'.
(Other definitions for thin that I've seen before include "Having little width" , "Narrow, slim" , "Slim - watery" , "Carrying little fat" , "Lean; narrow" .)