Dicky, given article and box, improvised (3,3,4)
I believe the answer is:
off the cuff
'improvised' is the definition.
(I've seen this before)
'dicky given article and box' is the wordplay.
I cannot really understand how this works, but
'article' could be 'the' (the 'definite article' part of speech) and 'the' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for off the cuff that I've seen before include "unprepared" , "Where one may lose shirt button" , "without thinking" , "Impromptu" , "From where you could lose a button" .)