So, while "cuss" doesn't have a direct meaning on its own, it's essentially a slang or informal shortening of "curse" and carries the same general sense of:
* To swear or use profanity.
* To utter a curse or invoke evil upon someone.
* To express annoyance, anger, or frustration.
In essence, "cuss" is a more casual and sometimes humorous way to refer to the act of cursing.