The word, not the concept. From the YouTube About, courtesy of Equality Now:

On 4 November 2013, Equality Now honored award-winning writer, director, producer and Advisory Board member, Joss Whedon, for his work on gender equality at its 'Make Equality Reality' event in Beverly Hills, California. Here, in his own words, he digs into the nature of the word 'feminist' and proposes an alternative.