IPA: //ˈkʌsɪdnəs//
KK: /ˈkʌsɪdnɪs/
The quality of being stubborn or difficult to deal with.
His cussedness made it hard for the team to work together.
Cussedness is formed from "cussed" (a variant of "cursed", from Old English "cursian", meaning to invoke evil upon) and the suffix "-ness" (meaning the state or quality of). The word "cussedness" refers to the state of being cursed or having a stubborn, ill-tempered nature.
Think of someone who is 'cursed' ('cussed') with a bad attitude, and the '-ness' indicates the quality of that attitude.