People in charge — like bosses and teachers — hate insubordination, which means that someone is defying their authority.
When a student is disrespectful to a teacher or says something like "I won't do this homework!", that's an act of insubordination. If a teacher didn't do what the principal wanted, that would also be insubordination. This word is often used in relation to the military, where giving and taking orders is extremely important. A soldier who commits insubordination — by disobeying an order — can be in a lot of trouble. Anywhere there's insubordination, someone with less power (a subordinate) is giving someone with more power a whole lot of trouble.