The adjective disaffected describes someone who is dissatisfied or rebellious. Usually if you're disaffected, you're upset with people in authority. You and your fellow disaffected workers might become so upset about the lack of raises that you decided to boycott work.
You might have heard the term "disaffected youth," which refers to young people rebelling against some aspect of society. For example, disaffected youth might fight against their lack of political freedom. Disaffected can also be used to describe things rather than people, like the disaffected lyrics in a song or the disaffected mood of a poem describing an unhappy or bitter state of mind. The word disaffected comes from disaffect, meaning "estranged, hostile."