Cheeky, say, about a bit of luck (5)
I believe the answer is:
saucy
'cheeky' is the definition.
(I've seen this in another clue)
'say about a bit of luck' is the wordplay.
'about' indicates putting letters inside.
'a bit of luck' becomes 'uc' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'say' placed around 'uc' is 'SAUCY'.
Can you help me to learn more?
(Other definitions for saucy that I've seen before include "Cheeky; risquZ" , "Impertinent - jaunty" , "Pert and toothsome" , "Cheeky, impertinent" , "Risque" .)