1. A person who can ease
their way through
things, typically using words. Also may be a player
. It seems this person may have a way with
words and always knows
what to say.
2. They may also be cunning, wily, and might be willing to lie, cheat, or steal to get what they want.
You can refer to the song "Smooth Operator" by Sade, read the lyrics, and it may help
It has good and bad connotation, it all depends on how it's used.
1. Dang, that girl don't look it, but she is one smooth operator. She just got a date
after a five minute conversation
2. That man is a smooth operator, he just dumped a girl and has a date
with two new ones.