defiance
They walked across the demarcation line, taking photographs of their act of defiance.
The demonstration is a pointless act of defiance against the government.
When we spoke our own language at home, it was a small act of defiance and resistance.
It was one of the bravest acts of defiance against a totalitarian regime that I had ever seen.
Revolutions sometimes begin with tiny acts of defiance rather than grand gestures.