Answer:
ill tempered
Explanation:
The author in the given is trying to convey that the behavior or the dealing of the individual was either hot tempered or disrespectful. The use of "vivacious" after alternately gives an example of dark or dull. However, the use of the word "sullen" represent Ill tempered and resentful. This clearly goes on to show that the actions of the said individual were ill tempered and dull in there nature.
