Clumsy writer going wrong way in Italian (5)
I believe the answer is:
inept
'clumsy' is the definition.
(I know that clumsy can be written as inept)
'writer going wrong way in italian' is the wordplay.
'writer' becomes 'pen' (something which writes).
'going wrong way' is a reversal indicator.
'in' is an insertion indicator.
'italian' becomes 'it' (abbreviation for Italian).
'pen' backwards is 'nep'.
'nep' put within 'it' is 'INEPT'.
(Other definitions for inept that I've seen before include "Unskilful or unsuitable" , "Ham-fisted" , "Lousy" , "Standard required in a piece of work (colloq.)" , "Clumsy, bungling" .)