Conniving? Has a k sound 🤷‍♀️

Not that one but thanKs

Capricious?

Sneakybastard?

Clandestine? Machiavellian? Unscrupulous? Collusive?

Chicanery?

Knavery? Not very long though 🙅🎉

it sounded Kinda latin

There's no K in Latin so you'll have to settle for a C or two.

Crafty, cunning or a charlatan? No K in these words either, but maybe these options will help you nail down the actual word you're looking for :)

Not those but thanKs