There are a lot of false definitions here.
Saucy is cheeky but usually with a "naughty" (as in sexy) undertone, but not always.
You could say that a young
child had a saucy grin, they might have done a
poo in their fathers
hat and then have a saucy grin like they know its wrong but they find it funny.
Or a little girl who has dressed up in her mothers clothes might walk around the street trying to walk in her mothers high heels and make up splattered all over her face, she is being saucy an old lady would say.
Carry on films, OOH SAUCY.
NOT
DRUNK etc.