free spirit

vapaa sielu One who is a nonconformist or who does not recognize the authority of others.
1904, w:Jack London|Jack London, The Sea Wolf, ch. 26:

But Lucifer was a free spirit. To serve was to suffocate.

Writing in the Victorian era, Scientist Ellis (Psychology of Sex) idolized Casanova as a free spirit, a man who had the courage to live life fully, and as a shining example of "adjustment"—for Casanova adapted himself so easily to his own desires.

To many bosses, a beard is a dangerous sign, like a neck tattoo or a pierced nose, that says, “I am a free spirit, not a team player.”