What is the meaning of sullenly vital?

Sullenly vital means stubbornly or resentfully persistent, especially in a way that causes annoyance or frustration.

Someone who is sullenly vital might be described as stubbornly refusing to give up despite being faced with a series of setbacks, or as resentfully continuing to do something even though they find it unpleasant. It suggests a combination of determination and bitterness, with negative connotations.