This is the 11983rd most frequent Russian word.
защищающим
"Defending" or "protecting."
In this sentence, 'защищающим' describes 'митинг', qualifying it as the one that defends animal rights prominently.
Она приняла участие в митинге, защищающим права животных.
She participated in the rally, defending animal rights.
Here, 'защищающим' modifies 'мужчина', indicating that he actively protected his friends, defining his actions.
Мужчина, защищающим своих друзей, стал героем дня.
The man, defending his friends, became the hero of the day.
In this example, 'защищающим' describes 'человек', signifying his role as a defender of freedom of speech.