indignant

angered at something unjust or wrong

Affected with indignation; wrathful; passionate; irate; feeling wrath, as when a person is exasperated by unworthy or unjust treatment, by a mean action, or by a degrading accusation.

Latin 'indignare' - to regard with indignation or resent

“A pretty little housemaid replied, with an indignant flush, that she was the person.”

— George Meredith, Complete Project Gutenberg Works of George Meredith

Stefan wandered Seoul's busy streets when a street vendor shortchanged him. Indignant at this injustice, he loudly demanded his proper change, drawing a crowd that laughed as thevendor sheepishly handed over the right amount. Stefan strode away with his dignity and won coins.

At dusk, Felix paced the Philosopher's Path near the Kinkaku-ji temple, his footsteps echoing off the ancient stone walls. When a group of tourists tossed their plastic bottles into the bushes, he snatched up one bright green bottle and hurled it back at them with an indignant glare that silenced their laughter.

“The Youth International Party (YIP) and Students for a Democratic Society (SDS) emerged in Li'l Abner as "Students Wildly Indignant about Nearly Everything!" (SWINE).”