Adjective
Monstrous– extremely, unusually large or very wrong or unfair
Definition 2- very ugly, cruel, or vicious
Story of an Hour By Kate Chopin 1984
“She did not stop to ask if it were or were not a monstrous joy that held her.”
The narrator used this word to see if their vicious joy that held her.
http://www.merriam-webster.com/dictionary/monstrous