Insolent often conveys strong disdain or contempt for authority or norms. His insolent tone made it clear he didn't care about the rules.
Pro Tip 2/3
Cultural Variance
What's considered insolent can vary by culture; study local manners to understand limits. While slouching is casual in one country, it might be seen as insolent in another.
Pro Tip 3/3
Non-Verbal Cues
Insolence can be shown through body language, not just words. Rolling her eyes at the request, she exhibited insolent behavior without a word.