a person who is opposed to the political system in their country and tries to change it using force

The rebels took over the capital and set up a new government. 叛乱分子占领了首都并成立了新政府。

rebel troops/fighters 反叛军队／战士

a person who does not like rules or authority, and shows this by behaving differently from most people in society

He was a rebel when he was a teenager and dyed his hair pink. 他十几岁的时候有些叛逆，把头发染成了粉红色。

to fight against the government

The people rebelled against the harsh new government. 人民起来反抗这个残暴的新政府。

to refuse to obey rules or people in authority

Jacob rebelled against his parents' plans for him and left school at the age of 16. 雅各布反抗父母替他做好的计划，在16岁就辍学了。

If you are too strict with teenagers, they often rebel. 如果你对青少年太严厉，他们往往会反叛。

to react against a feeling, action, plan, etc.

My poor sick stomach rebelled at the idea of any more food. 我的胃不太好，连想到食物都会反胃。