The quality of being like a snake, especially in a sneaky or deceitful way.
Snakiness is usually seen as a bad thing because it means someone is being sneaky or dishonest.
Examples:
I don't like the snakiness of that person.
Her snakiness made it hard to trust her.
The snakiness of his behavior was very obvious.
The snakiness of the fox was not appreciated by the other animals.
The snakiness of the villain made the story more interesting.
The snakiness of the salesman was so obvious, nobody wanted to buy from him.