An iconoclast is someone who challenges or attacks widely held beliefs, traditions, or institutions that others consider sacred or untouchable.

When Galileo argued that Earth orbited the sun rather than sitting at the center of the universe, he was being an iconoclast: he challenged what many people of his time “knew” to be true. When the Wright brothers insisted that humans could fly in heavier-than-air machines, other scientists mocked them as iconoclasts for going against accepted wisdom.

Iconoclasts often face resistance because they're attacking ideas that feel comfortable and familiar. A student who questions why everyone has to solve math problems the same way, or an inventor who thinks there's a better design for something everyone uses, shows iconoclastic thinking.

Not all iconoclasts are right, though: some people challenge traditions just to be different or controversial. Many iconoclasts have good reasons for their challenges and may offer better alternatives. History tends to celebrate iconoclasts who were proven correct, like scientists and inventors who overturned old misconceptions. But in their own time, iconoclasts often face ridicule or opposition from people defending the status quo.