Bit by bit (9)
'bit by bit' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for piecemeal that I've seen before include "A bit at a time" , "by degrees" , "Unsystematically" , "Claim epee in gradual unsystematic way" , "a little at a time" .)
(Other definitions for gradually that I've seen before include "A little at a time - slowly" , "Developing slowly and by degrees" , "slowly but surely" , "over a period?" , "Bit by bit" .)