Carry on being ambitious (2-5)
I believe the answer is:
go-ahead
'ambitious' is the definition.
(I've seen this before)
'carry on being' is the wordplay.
I cannot really see how this works, but
'being' could be 'head' (head is a kind of being) and 'head' is present in the answer.
The remaining letters 'goa' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for go-ahead that I've seen before include "Pioneering (green light?)" , "Up-and-coming - authorisation" , "Enterprising" , "Permission to proceed" , "Enterprisingly progressive" .)