One who is grossly sneaky, and or irregularly efficient at anything "Cloak and dagger", also, one who is generally good with the ladies.
-see also: anyone named Sean, Brendan, Devlin, and Noah, as all people with these names are sneaky (and good with the ladies) by nature.
That Sean is a Sly Casanova.

Those guys, they're Sly Casanovas.

Man, I wish I was a Sly Casanova.

by Michael Burbanks May 14, 2006
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