Cheeky, say, about a bit of luck (5)
I believe the answer is:
saucy
'cheeky' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
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" .)