Racial profiling is the practice of targeting particular people because of their ethnic background or race. A profile is an outline of a face. Racial profiling is judging someone based only on an outline — the person’s race.
Racial profiling is a form of institutional racism. Sometimes police officers, security workers, and other law enforcement officials are accused of racial profiling. When a driver is stopped and searched solely because of her skin color, that's racial profiling. And when a passenger is asked to leave an airplane because the hijab she's wearing makes other passengers nervous, that's also racial profiling.