What is Sneakily?

When someone is mean, but on the low-key. You'd think they'd be a nice person, but they aren't.

"Yeah I don't like that class" "But everyone's supposed to be nice I've heard" "Exactly. They're sneakily mean"

Sneakily - meme gif

In a Sneaky fashion. Typically used to describe an action in a D&D encounter.

I sneakily run past the dragon.

It's just the adverbial form of sneak or sneaky. It's not a real word and it damned well should be!

I went into Dr. Aweful's mountain lab sneakily, and stole his blueprints for a flying monkey machine!

I followed bob sneakily around the building and scaried him.

The act of being sneaky. Performing actions in a sneaky way.

He was sneakily sending text messages to his mistress as his wife watched the kids.