What does cussedest mean?

"Cussest" is a dialectal, particularly Southern US, variation of "cursedest," which is the superlative form of "cursed." It means the most cursed or the most troublesome/difficult/annoying.

It's often used in a humorous or exasperated way, as in:

* "That's the cussedest dog I ever did see!"

* "This darned rain is the cussedest thing, it just won't stop!"

It's important to note that while "cussedest" is often used in a lighthearted way, it does carry the connotation of something being unpleasant or difficult.